Linux Fundamentals, Part 2 - Revision history

http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&feed=atom&action=history Linux Fundamentals, Part 2 - Revision history 2013-06-19T21:18:34Z Revision history for this page on the wiki MediaWiki 1.20.6 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=8971&oldid=prev 121.33.190.179: /* The "*" metacharacter */ 2013-03-06T13:58:47Z

<p>‎<span dir="auto"><span class="autocomment">The "*" metacharacter</span></span></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 13:58, 6 March 2013</td> </tr><tr><td colspan="2" class="diff-lineno">Line 82:</td> <td colspan="2" class="diff-lineno">Line 82:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* b[cq]*e matches bccqqe but not bccc (if a glob, it would match the first but not the second as well)</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* b[cq]*e matches bccqqe but not bccc (if a glob, it would match the first but not the second as well)</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* b[cq]*e matches bqqcce but not cqe (if a glob, it would match the first but not the second as well)</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* b[cq]*e matches bqqcce but not cqe (if a glob, it would match the first but not the second as well)</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>* b[cq]*e <del class="diffchange diffchange-inline">matches </del>bbbeee (this would not be the case with a glob)</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>* b[cq]*e <ins class="diffchange diffchange-inline">doesn't match </ins>bbbeee (this would not be the case with a glob)</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* .* will match any string. (if a glob, it would match any string starting with .)</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* .* will match any string. (if a glob, it would match any string starting with .)</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* foo.* will match any string that begins with foo (if a glob, it would match any string starting with the four literal characters foo..)</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>* foo.* will match any string that begins with foo (if a glob, it would match any string starting with the four literal characters foo..)</div></td></tr>  </table>

121.33.190.179 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=8270&oldid=prev Oleg: Reverted edits by 117.240.182.23 (talk) to last revision by Big Fun 2012-12-04T05:33:28Z

<p>Reverted edits by <a href="/wiki/Special:Contributions/117.240.182.23" title="Special:Contributions/117.240.182.23">117.240.182.23</a> (<a href="/index.php?title=User_talk:117.240.182.23&action=edit&redlink=1" class="new" title="User talk:117.240.182.23 (page does not exist)">talk</a>) to last revision by <a href="/wiki/Special:FormEdit/Person/User:Big_Fun?redlink=1" class="new" title="User:Big Fun (page does not exist)">Big Fun</a></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 05:33, 4 December 2012</td> </tr><tr><td colspan="2" class="diff-lineno">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">qw0gJi  <a href</del>="<del class="diffchange diffchange-inline">http://gyiuvtouljlr.com/</del>"<del class="diffchange diffchange-inline">>gyiuvtouljlr</</del>a<del class="diffchange diffchange-inline">></del>, <del class="diffchange diffchange-inline">[url=http://rxebjstuexef</del>.<del class="diffchange diffchange-inline">com/]rxebjstuexef[/url]</del>, <del class="diffchange diffchange-inline">[link=http://mobejbcnpzid</del>.<del class="diffchange diffchange-inline">com/]mobejbcnpzid</del>[<del class="diffchange diffchange-inline">/link</del>], <del class="diffchange diffchange-inline">http://cbznrnvefjzi</del>.<del class="diffchange diffchange-inline">com/</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>=<ins class="diffchange diffchange-inline">= Before You Start ==</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div> </div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== About this tutorial ===</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">Welcome to </ins>"<ins class="diffchange diffchange-inline">Basic administration,</ins>" <ins class="diffchange diffchange-inline">the second of four tutorials designed to prepare you for the Linux Professional Institute's 101 exam. In this tutorial, we'll show you how to use regular expressions to search files for text patterns. Next, we'll introduce you to the Filesystem Hierarchy Standard (FHS), and then show you how to locate files on your system. Then, we'll show you how to take full control of Linux processes by running them in the background, listing processes, detaching processes from the terminal, and more. Next, we'll give you </ins>a <ins class="diffchange diffchange-inline">whirlwind introduction to shell pipelines</ins>, <ins class="diffchange diffchange-inline">redirection, and text processing commands</ins>. <ins class="diffchange diffchange-inline">Finally</ins>, <ins class="diffchange diffchange-inline">we'll introduce you to Linux kernel modules</ins>.</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div> </div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">This particular tutorial (Part 2) is ideal for those who have a good basic knowledge of bash and want to receive a solid introduction to basic Linux administration tasks. If you are new to Linux, we recommend that you complete </ins>[<ins class="diffchange diffchange-inline">[Linux Fundamentals, Part 1|Part 1</ins>]<ins class="diffchange diffchange-inline">] of this tutorial series first before continuing. For some, much of this material will be new, but more experienced Linux users may find this tutorial to be a great way of "rounding out" their basic Linux administration skills.</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div> </div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">For those who have taken the release 1 version of this tutorial for reasons other than LPI exam preparation, you probably don't need to take this one. However, if you do plan to take the exams</ins>, <ins class="diffchange diffchange-inline">you should strongly consider reading this revised tutorial</ins>.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Regular Expressions ==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Regular Expressions ==</div></td></tr>  </table>

Oleg http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=8269&oldid=prev 117.240.182.23: qw0gJi <a href="http://gyiuvtouljlr.com/">gyiuvtouljlr</a>, [url=http://rxebjstuexef.com/]rxebjstuexef[/url], [link=http://mobejbcnpzid.com/]mobejbcnpzid[/link], http://cbznrnvefjzi.com/ 2012-12-03T11:11:33Z

<p>qw0gJi <a href="http://gyiuvtouljlr.com/">gyiuvtouljlr</a>, [url=http://rxebjstuexef.com/]rxebjstuexef[/url], [link=http://mobejbcnpzid.com/]mobejbcnpzid[/link], http://cbznrnvefjzi.com/</p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 11:11, 3 December 2012</td> </tr><tr><td colspan="2" class="diff-lineno">Line 1:</td> <td colspan="2" class="diff-lineno">Line 1:</td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>=<del class="diffchange diffchange-inline">= Before You Start ==</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">qw0gJi  <a href</ins>="<ins class="diffchange diffchange-inline">http://gyiuvtouljlr.com/</ins>"<ins class="diffchange diffchange-inline">>gyiuvtouljlr</</ins>a<ins class="diffchange diffchange-inline">></ins>, <ins class="diffchange diffchange-inline">[url=http://rxebjstuexef</ins>.<ins class="diffchange diffchange-inline">com/]rxebjstuexef[/url]</ins>, <ins class="diffchange diffchange-inline">[link=http://mobejbcnpzid</ins>.<ins class="diffchange diffchange-inline">com/]mobejbcnpzid</ins>[<ins class="diffchange diffchange-inline">/link</ins>], <ins class="diffchange diffchange-inline">http://cbznrnvefjzi</ins>.<ins class="diffchange diffchange-inline">com/</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">=== About this tutorial ===</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">Welcome to </del>"<del class="diffchange diffchange-inline">Basic administration,</del>" <del class="diffchange diffchange-inline">the second of four tutorials designed to prepare you for the Linux Professional Institute's 101 exam. In this tutorial, we'll show you how to use regular expressions to search files for text patterns. Next, we'll introduce you to the Filesystem Hierarchy Standard (FHS), and then show you how to locate files on your system. Then, we'll show you how to take full control of Linux processes by running them in the background, listing processes, detaching processes from the terminal, and more. Next, we'll give you </del>a <del class="diffchange diffchange-inline">whirlwind introduction to shell pipelines</del>, <del class="diffchange diffchange-inline">redirection, and text processing commands</del>. <del class="diffchange diffchange-inline">Finally</del>, <del class="diffchange diffchange-inline">we'll introduce you to Linux kernel modules</del>.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">This particular tutorial (Part 2) is ideal for those who have a good basic knowledge of bash and want to receive a solid introduction to basic Linux administration tasks. If you are new to Linux, we recommend that you complete </del>[<del class="diffchange diffchange-inline">[Linux Fundamentals, Part 1|Part 1</del>]<del class="diffchange diffchange-inline">] of this tutorial series first before continuing. For some, much of this material will be new, but more experienced Linux users may find this tutorial to be a great way of "rounding out" their basic Linux administration skills.</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">For those who have taken the release 1 version of this tutorial for reasons other than LPI exam preparation, you probably don't need to take this one. However, if you do plan to take the exams</del>, <del class="diffchange diffchange-inline">you should strongly consider reading this revised tutorial</del>.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Regular Expressions ==</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>== Regular Expressions ==</div></td></tr>  </table>

117.240.182.23 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4116&oldid=prev Big Fun at 19:17, 11 May 2011 2011-05-11T19:17:21Z

<p></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 19:17, 11 May 2011</td> </tr><tr><td colspan="2" class="diff-lineno">Line 268:</td> <td colspan="2" class="diff-lineno">Line 268:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>-rw-------    1 root    root            0 Jan  4 18:00 d</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>-rw-------    1 root    root            0 Jan  4 18:00 d</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ date</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ date</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Mon <del class="diffchange diffchange-inline">May </del> 7 18:14:52 EST 2003</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Mon <ins class="diffchange diffchange-inline">Jan </ins> 7 18:14:52 EST 2003</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div></pre></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div></pre></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>You could search for files that were created in the past 24 hours:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>You could search for files that were created in the past 24 hours:</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 290:</td> <td colspan="2" class="diff-lineno">Line 290:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>./c</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>./c</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ls -l b c</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ls -l b c</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>-rw-------    1 root    root            0 <del class="diffchange diffchange-inline">May </del> 6 18:00 b</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>-rw-------    1 root    root            0 <ins class="diffchange diffchange-inline">Jan </ins> 6 18:00 b</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>-rw-------    1 root    root            0 <del class="diffchange diffchange-inline">May </del> 5 18:00 c</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>-rw-------    1 root    root            0 <ins class="diffchange diffchange-inline">Jan </ins> 5 18:00 c</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div></pre></div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div></pre></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>  </table>

Big Fun http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4115&oldid=prev Rh1 at 17:03, 25 March 2011 2011-03-25T17:03:01Z

<p></p> <a href="http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4115&oldid=4114">Show changes</a>

Rh1 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4114&oldid=prev Rh1 at 16:12, 25 March 2011 2011-03-25T16:12:29Z

<p></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 16:12, 25 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno">Line 598:</td> <td colspan="2" class="diff-lineno">Line 598:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><span style="color:green">tr</span> is a character translation tool; it's used to map certain characters in the input stream to certain other characters in the output stream.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div><span style="color:green">tr</span> is a character translation tool; it's used to map certain characters in the input stream to certain other characters in the output stream.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>sed is a powerful stream-oriented text editor. You can learn more about sed in the following Funtoo articles:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>sed<ins class="diffchange diffchange-inline"></span> </ins>is a powerful stream-oriented text editor. You can learn more about sed in the following Funtoo articles:</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">    </del>* Sed by <del class="diffchange diffchange-inline">example</del>, Part 1</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>* <ins class="diffchange diffchange-inline">[[</ins>Sed by <ins class="diffchange diffchange-inline">Example</ins>, Part 1<ins class="diffchange diffchange-inline">]]</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">    </del>* Sed by <del class="diffchange diffchange-inline">example</del>, Part 2</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>* <ins class="diffchange diffchange-inline">[[</ins>Sed by <ins class="diffchange diffchange-inline">Example</ins>, Part 2<ins class="diffchange diffchange-inline">]]</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">    </del>* Sed by <del class="diffchange diffchange-inline">example</del>, Part 3</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>* <ins class="diffchange diffchange-inline">[[</ins>Sed by <ins class="diffchange diffchange-inline">Example</ins>, Part 3<ins class="diffchange diffchange-inline">]]</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>If you're planning to take the LPI exam, be sure to read the first two articles of this series.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>If you're planning to take the LPI exam, be sure to read the first two articles of this series.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>awk is a handy line-oriented text-processing language. To learn more about awk, read the following Funtoo articles:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>awk<ins class="diffchange diffchange-inline"></span> </ins>is a handy line-oriented text-processing language. To learn more about awk, read the following Funtoo articles:</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">    </del>* Awk by <del class="diffchange diffchange-inline">example</del>, Part 1</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>* <ins class="diffchange diffchange-inline">[[</ins>Awk by <ins class="diffchange diffchange-inline">Example</ins>, Part 1<ins class="diffchange diffchange-inline">]]</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">    </del>* Awk by <del class="diffchange diffchange-inline">example</del>, Part 2</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>* <ins class="diffchange diffchange-inline">[[</ins>Awk by <ins class="diffchange diffchange-inline">Example</ins>, Part 2<ins class="diffchange diffchange-inline">]]</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">    </del>* Awk by <del class="diffchange diffchange-inline">example</del>, Part 3</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>* <ins class="diffchange diffchange-inline">[[</ins>Awk by <ins class="diffchange diffchange-inline">Example</ins>, Part 3<ins class="diffchange diffchange-inline">]]</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>od is designed to transform the input stream into a octal or hex "dump" format.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>od<ins class="diffchange diffchange-inline"></span> </ins>is designed to transform the input stream into a octal or hex "dump" format.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>split is a command used to split a larger file into many smaller-sized, more manageable chunks.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>split<ins class="diffchange diffchange-inline"></span> </ins>is a command used to split a larger file into many smaller-sized, more manageable chunks.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>fmt will reformat paragraphs so that wrapping is done at the margin. These days it's less useful since this ability is built into most text editors, but it's still a good one to know.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>fmt<ins class="diffchange diffchange-inline"></span> </ins>will reformat paragraphs so that wrapping is done at the margin. These days it's less useful since this ability is built into most text editors, but it's still a good one to know.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>paste takes two or more files as input, concatenates each sequential line from the input files, and outputs the resulting lines. It can be useful to create tables or columns of text.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>paste<ins class="diffchange diffchange-inline"></span> </ins>takes two or more files as input, concatenates each sequential line from the input files, and outputs the resulting lines. It can be useful to create tables or columns of text.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>join is similar to paste, but it uses a field (by default the first) in each input line to match up what should be combined on a single line.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>join<ins class="diffchange diffchange-inline"></span> </ins>is similar to paste, but it uses a field (by default the first) in each input line to match up what should be combined on a single line.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>tee prints its input both to a file and to the screen. This is useful when you want to create a log of something, but you also want to see it on the screen.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>tee<ins class="diffchange diffchange-inline"></span> </ins>prints its input both to a file and to the screen. This is useful when you want to create a log of something, but you also want to see it on the screen.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">Whirlwind over! Redirection</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Similar to using > on the bash command line, you can also use < to redirect a file into a command. For many commands, you can simply specify the filename on the command line, however some commands only work from standard input.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== Whirlwind over! Redirection ===</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Similar to using <ins class="diffchange diffchange-inline"><span style="color:green">></span</ins>> on the bash command line, you can also use <<ins class="diffchange diffchange-inline">span style="color:green">&lt;</span> </ins>to redirect a file into a command. For many commands, you can simply specify the filename on the command line, however some commands only work from standard input.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Bash and other shells support the concept of a "herefile." This allows you to specify the input to a command in the lines following the command invocation, terminating it with a sentinal value. This is easiest shown through an example:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Bash and other shells support the concept of a "herefile." This allows you to specify the input to a command in the lines following the command invocation, terminating it with a sentinal value. This is easiest shown through an example:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ sort <<END</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ sort <<END</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>apple</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>apple</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 637:</td> <td colspan="2" class="diff-lineno">Line 637:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>banana</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>banana</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>cranberry</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>cranberry</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">In the example above, we typed the words apple, cranberry and banana, followed by "END" to signify the end of the input. The <span style="color:green">sort</span> program then returned our words in alphabetical order.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">In the example above, we typed the words apple, cranberry and banana, followed by "END" to signify the end of the input. The sort program then returned our words in alphabetical order.</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>Using >> <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Using >></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>You would expect <ins class="diffchange diffchange-inline"><span style="color:green"</ins>><ins class="diffchange diffchange-inline">>></span</ins>> to be somehow analogous to <<ins class="diffchange diffchange-inline">span style="color:green">&lt;&lt;</ins><<ins class="diffchange diffchange-inline">/span></ins>, but it isn't really. It simply means to append the output to a file, rather than overwrite as <ins class="diffchange diffchange-inline"><span style="color:green">></span</ins>> would. For example:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>You would expect >> to be somehow analogous to <<, but it isn't really. It simply means to append the output to a file, rather than overwrite as > would. For example:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo Hi > myfile</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo Hi > myfile</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo there. > myfile</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo there. > myfile</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ cat myfile</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ cat myfile</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>there.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>there.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Oops! We lost the "Hi" portion! What we meant was this:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Oops! We lost the "Hi" portion! What we meant was this:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo Hi > myfile</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo Hi > myfile</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo there. >> myfile</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo there. >> myfile</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 655:</td> <td colspan="2" class="diff-lineno">Line 655:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Hi</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Hi</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>there.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>there.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Much better!</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Much better!</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">Kernel Modules</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">Meet "uname"</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">== Kernel Modules ==</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== Meet "uname" ===</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The uname command provides a variety of interesting information about your system. Here's what is displayed on my development workstation when I type uname -a which tells the uname command to print out all of its information in one swoop:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The uname command provides a variety of interesting information about your system. Here's what is displayed on my development workstation when I type uname -a which tells the uname command to print out all of its information in one swoop:</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>  </table>

Rh1 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4113&oldid=prev Rh1 at 14:33, 25 March 2011 2011-03-25T14:33:42Z

<p></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 14:33, 25 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno">Line 526:</td> <td colspan="2" class="diff-lineno">Line 526:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>=== Redirection revisited ===</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>=== Redirection revisited ===</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Earlier in this tutorial series, we saw an example of how to use the > operator to redirect the output of a command to a file, as follows:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Earlier in this tutorial series, we saw an example of how to use the <ins class="diffchange diffchange-inline"><span style="color:green">></span</ins>> operator to redirect the output of a command to a file, as follows:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo "firstfile" > copyme</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo "firstfile" > copyme</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>In addition to redirecting output to a file, we can also take advantage of a powerful shell feature called pipes. Using pipes, we can pass the output of one command to the input of another command. Consider the following example:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>In addition to redirecting output to a file, we can also take advantage of a powerful shell feature called pipes. Using pipes, we can pass the output of one command to the input of another command. Consider the following example:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo "hi there" | wc</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ echo "hi there" | wc</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>       1      2      9</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>       1      2      9</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The <span style="color:green">|</span> character is used to connect the output of the command on the left to the input of the command on the right. In the example above, the <span style="color:green">echo</span> command prints out the string "hi there" followed by a linefeed. That output would normally appear on the terminal, but the pipe redirects it into the <span style="color:green">wc</span> command, which displays the number of lines, words, and characters in its input.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">The | character is used to connect the output of the command on the left to the input of the command on the right. In the example above, the echo command prints out the string "hi there" followed by a linefeed. That output would normally appear on the terminal, but the pipe redirects it into the wc command, which displays the number of lines, words, and characters in its input.</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>A pipe example <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>A pipe example</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Here is another simple example:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Here is another simple example:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ls -s | sort -n</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ls -s | sort -n</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>In this case, ls -s would normally print a listing of the current directory on the terminal, preceding each file with its size. But instead we've piped the output into sort -n, which sorts the output numerically. This is a really useful way to find large files in your home directory!</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>In this case, <ins class="diffchange diffchange-inline"><span style="color:green"></ins>ls -s<ins class="diffchange diffchange-inline"></span> </ins>would normally print a listing of the current directory on the terminal, preceding each file with its size. But instead we've piped the output into <ins class="diffchange diffchange-inline"><span style="color:green"></ins>sort -n<ins class="diffchange diffchange-inline"></span></ins>, which sorts the output numerically. This is a really useful way to find large files in your home directory!</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The following examples are more complex, but they demonstrate the power that can be harnessed using pipes. We're going to throw out some commands we haven't covered yet, but don't let that slow you down. Concentrate instead on understanding how pipes work so you can employ them in your daily Linux tasks.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The following examples are more complex, but they demonstrate the power that can be harnessed using pipes. We're going to throw out some commands we haven't covered yet, but don't let that slow you down. Concentrate instead on understanding how pipes work so you can employ them in your daily Linux tasks.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">The decompression pipeline</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== The decompression pipeline ===</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Normally to decompress and untar a file, you might do the following:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Normally to decompress and untar a file, you might do the following:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ bzip2 -d linux-2.4.16.tar.bz2</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ bzip2 -d linux-2.4.16.tar.bz2</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ tar xvf linux-2.4.16.tar</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ tar xvf linux-2.4.16.tar</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>The downside of this method is that it requires the creation of an intermediate, uncompressed file on your disk. Since tar has the ability to read directly from its input (instead of specifying a file), we could produce the same end-result using a pipeline:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>The downside of this method is that it requires the creation of an intermediate, uncompressed file on your disk. Since <ins class="diffchange diffchange-inline"><span style="color:green"></ins>tar<ins class="diffchange diffchange-inline"></span> </ins>has the ability to read directly from its input (instead of specifying a file), we could produce the same end-result using a pipeline:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ bzip2 -dc linux-2.4.16.tar.bz2 | tar xvf -</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ bzip2 -dc linux-2.4.16.tar.bz2 | tar xvf -</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Woo hoo! Our compressed tarball has been extracted and we didn't need an intermediate file.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Woo hoo! Our compressed tarball has been extracted and we didn't need an intermediate file.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">A longer pipeline</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== A longer pipeline ===</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Here's another pipeline example:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Here's another pipeline example:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ cat myfile.txt | sort | uniq | wc -l</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ cat myfile.txt | sort | uniq | wc -l</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>We use cat to feed the contents of myfile.txt to the sort command. When the sort command receives the input, it sorts all input lines so that they are in alphabetical order, and then sends the output to uniq. uniq removes any duplicate lines (and requires its input to be sorted, by the way,) sending the scrubbed output to wc -l. We've seen the wc command earlier, but without command-line options. When given the -l option, it only prints the number of lines in its input, instead of also including words and characters. You'll see that this pipeline will print out the number of unique (non-identical) lines in a text file.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>We use <ins class="diffchange diffchange-inline"><span style="color:green"></ins>cat<ins class="diffchange diffchange-inline"></span> </ins>to feed the contents of <ins class="diffchange diffchange-inline">'''</ins>myfile.txt<ins class="diffchange diffchange-inline">''' </ins>to the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>sort<ins class="diffchange diffchange-inline"></span> </ins>command. When the sort command receives the input, it sorts all input lines so that they are in alphabetical order, and then sends the output to <ins class="diffchange diffchange-inline"><span style="color:green"></ins>uniq<ins class="diffchange diffchange-inline"></span></ins>. <ins class="diffchange diffchange-inline"><span style="color:green"></ins>uniq<ins class="diffchange diffchange-inline"></span> </ins>removes any duplicate lines (and requires its input to be sorted, by the way,) sending the scrubbed output to <ins class="diffchange diffchange-inline"><span style="color:green"></ins>wc -l<ins class="diffchange diffchange-inline"></span></ins>. We've seen the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>wc<ins class="diffchange diffchange-inline"></span> </ins>command earlier, but without command-line options. When given the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>-l<ins class="diffchange diffchange-inline"></span> </ins>option, it only prints the number of lines in its input, instead of also including words and characters. You'll see that this pipeline will print out the number of unique (non-identical) lines in a text file.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Try creating a couple of test files with your favorite text editor and use this pipeline to see what results you get.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Try creating a couple of test files with your favorite text editor and use this pipeline to see what results you get.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">The text processing whirlwind begins</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Now we embark on a whirlwind tour of the standard Linux text processing commands. Because we're covering a lot of material in this tutorial, we don't have the space to provide examples for every command. Instead, we encourage you to read each command's man page (by typing man echo, for example) and learn how each command and it's options work by spending some time playing with each one. As a rule, these commands print the results of any text processing to the terminal rather than modifying any specified files. After we take our whirlwind tour of the standard Linux text processing commands, we'll take a closer look at output and input redirection. So yes, there is light at the end of the tunnel :)</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== The text processing whirlwind begins ===</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Now we embark on a whirlwind tour of the standard Linux text processing commands. Because we're covering a lot of material in this tutorial, we don't have the space to provide examples for every command. Instead, we encourage you to read each command's man page (by typing <ins class="diffchange diffchange-inline"><span style="color:green"></ins>man echo<ins class="diffchange diffchange-inline"></span></ins>, for example) and learn how each command and it's options work by spending some time playing with each one. As a rule, these commands print the results of any text processing to the terminal rather than modifying any specified files. After we take our whirlwind tour of the standard Linux text processing commands, we'll take a closer look at output and input redirection. So yes, there is light at the end of the tunnel :)</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>echo prints its arguments to the terminal. Use the -e option if you want to embed backslash escape sequences; for example echo -e "foo\nfoo" will print foo, then a newline, and then foo again. Use the -n option to tell echo to omit the trailing newline that is appended to the output by default.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>echo<ins class="diffchange diffchange-inline"></span> </ins>prints its arguments to the terminal. Use the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>-e<ins class="diffchange diffchange-inline"></span> </ins>option if you want to embed backslash escape sequences; for example <ins class="diffchange diffchange-inline"><span style="color:green"></ins>echo -e "foo\nfoo"<ins class="diffchange diffchange-inline"></span> </ins>will print foo, then a newline, and then foo again. Use the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>-n<ins class="diffchange diffchange-inline"></span> </ins>option to tell echo to omit the trailing newline that is appended to the output by default.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>cat will print the contents of the files specified as arguments to the terminal. Handy as the first command of a pipeline, for example, cat foo.txt | blah.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>cat<ins class="diffchange diffchange-inline"></span> </ins>will print the contents of the files specified as arguments to the terminal. Handy as the first command of a pipeline, for example, <ins class="diffchange diffchange-inline"><span style="color:green"></ins>cat foo.txt | blah<ins class="diffchange diffchange-inline"></span></ins>.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>sort will print the contents of the file specified on the command line in alphabetical order. Of course, sort also accepts piped input. Type man sort to familiarize yourself with its various options that control sorting behavior.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>sort<ins class="diffchange diffchange-inline"></span> </ins>will print the contents of the file specified on the command line in alphabetical order. Of course, <ins class="diffchange diffchange-inline"><span style="color:green"></ins>sort<ins class="diffchange diffchange-inline"></span> </ins>also accepts piped input. Type <ins class="diffchange diffchange-inline"><span style="color:green"></ins>man sort<ins class="diffchange diffchange-inline"></span> </ins>to familiarize yourself with its various options that control sorting behavior.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>uniq takes an already-sorted file or stream of data (via a pipeline) and removes duplicate lines.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>uniq<ins class="diffchange diffchange-inline"></span> </ins>takes an already-sorted file or stream of data (via a pipeline) and removes duplicate lines.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>wc prints out the number of lines, words, and bytes in the specified file or in the input stream (from a pipeline). Type man wc to learn how to fine-tune what counts are displayed.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>wc<ins class="diffchange diffchange-inline"></span> </ins>prints out the number of lines, words, and bytes in the specified file or in the input stream (from a pipeline). Type <ins class="diffchange diffchange-inline"><span style="color:green"></ins>man wc<ins class="diffchange diffchange-inline"></span> </ins>to learn how to fine-tune what counts are displayed.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>head prints out the first ten lines of a file or stream. Use the -n option to specify how many lines should be displayed.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>head<ins class="diffchange diffchange-inline"></span> </ins>prints out the first ten lines of a file or stream. Use the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>-n<ins class="diffchange diffchange-inline"></span> </ins>option to specify how many lines should be displayed.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>tail prints out the last ten lines of a file or stream. Use the -n option to specify how many lines should be displayed.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>tail<ins class="diffchange diffchange-inline"></span> </ins>prints out the last ten lines of a file or stream. Use the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>-n<ins class="diffchange diffchange-inline"></span> </ins>option to specify how many lines should be displayed.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>tac is like cat, but prints all lines in reverse order; in other words, the last line is printed first.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>tac<ins class="diffchange diffchange-inline"></span> </ins>is like <ins class="diffchange diffchange-inline"><span style="color:green"></ins>cat<ins class="diffchange diffchange-inline"></span></ins>, but prints all lines in reverse order; in other words, the last line is printed first.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>expand converts input tabs to spaces. Use the -t option to specify the tabstop.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>expand<ins class="diffchange diffchange-inline"></span> </ins>converts input tabs to spaces. Use the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>-t<ins class="diffchange diffchange-inline"></span> </ins>option to specify the tabstop.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>unexpand converts input spaces to tabs. Use the -t option to specify the tabstop.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>unexpand<ins class="diffchange diffchange-inline"></span> </ins>converts input spaces to tabs. Use the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>-t<ins class="diffchange diffchange-inline"></span> </ins>option to specify the tabstop.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>cut is used to extract character-delimited fields from each line of an input file or stream.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>cut<ins class="diffchange diffchange-inline"></span> </ins>is used to extract character-delimited fields from each line of an input file or stream.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>The nl command adds a line number to every line of input. Useful for printouts.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>The <ins class="diffchange diffchange-inline"><span style="color:green"></ins>nl<ins class="diffchange diffchange-inline"></span> </ins>command adds a line number to every line of input. Useful for printouts.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>pr is used to break files into multiple pages of output; typically used for printing.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>pr<ins class="diffchange diffchange-inline"></span> </ins>is used to break files into multiple pages of output; typically used for printing.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>tr is a character translation tool; it's used to map certain characters in the input stream to certain other characters in the output stream.</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><span style="color:green"></ins>tr<ins class="diffchange diffchange-inline"></span> </ins>is a character translation tool; it's used to map certain characters in the input stream to certain other characters in the output stream.</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>sed is a powerful stream-oriented text editor. You can learn more about sed in the following Funtoo articles:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>sed is a powerful stream-oriented text editor. You can learn more about sed in the following Funtoo articles:</div></td></tr>  </table>

Rh1 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4112&oldid=prev Rh1 at 14:06, 25 March 2011 2011-03-25T14:06:56Z

<p></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 14:06, 25 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno">Line 441:</td> <td colspan="2" class="diff-lineno">Line 441:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>=== Using ps to list processes ===</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>=== Using ps to list processes ===</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>The jobs command we were using earlier only lists processes that were started from your bash session. To see all the processes on your system, use ps with the a and x options together:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>The <ins class="diffchange diffchange-inline"><span style="color:green"></ins>jobs<ins class="diffchange diffchange-inline"></span> </ins>command we were using earlier only lists processes that were started from your bash session. To see all the processes on your system, use <ins class="diffchange diffchange-inline"><span style="color:green"></ins>ps<ins class="diffchange diffchange-inline"></span> </ins>with the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>a<ins class="diffchange diffchange-inline"></span> </ins>and <ins class="diffchange diffchange-inline"><span style="color:green"></ins>x<ins class="diffchange diffchange-inline"></span> </ins>options together:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps ax</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps ax</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   PID TTY      STAT  TIME COMMAND</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   PID TTY      STAT  TIME COMMAND</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 450:</td> <td colspan="2" class="diff-lineno">Line 450:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>     4 ?        SW    2:33 [kswapd]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>     4 ?        SW    2:33 [kswapd]</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>     5 ?        SW    0:00 [bdflush]</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>     5 ?        SW    0:00 [bdflush]</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">I've only listed the first few because it is usually a very long list. This gives you a snapshot of what the whole machine is doing, but is a lot of information to sift through. If you were to leave off the <span style="color:green">ax</span>, you would see only processes that are owned by you, and that have a controlling terminal. The command <span style="color:green">ps x</span> would show you all your processes, even those without a controlling terminal. If you were to use <span style="color:green">ps a</span>, you would get the list of everybody's processes that are attached to a terminal.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">I've only listed the first few because it is usually a very long list. This gives you a snapshot of what the whole machine is doing, but is a lot of information to sift through. If you were to leave off the ax, you would see only processes that are owned by you, and that have a controlling terminal. The command ps x would show you all your processes, even those without a controlling terminal. If you were to use ps a, you would get the list of everybody's processes that are attached to a terminal.</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>Seeing the forest and the trees <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Seeing the forest and the trees</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>You can also list different information about each process. The <ins class="diffchange diffchange-inline"><span style="color:green"></ins>--forest<ins class="diffchange diffchange-inline"></span> </ins>option makes it easy to see the process hierarchy, which will give you an indication of how the various processes on your system interrelate. When a process starts a new process, that new process is called a "child" process. In a <ins class="diffchange diffchange-inline"><span style="color:green"></ins>--forest<ins class="diffchange diffchange-inline"></span> </ins>listing, parents appear on the left, and children appear as branches to the right:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>You can also list different information about each process. The --forest option makes it easy to see the process hierarchy, which will give you an indication of how the various processes on your system interrelate. When a process starts a new process, that new process is called a "child" process. In a --forest listing, parents appear on the left, and children appear as branches to the right:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps x --forest</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps x --forest</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   PID TTY      STAT  TIME COMMAND</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   PID TTY      STAT  TIME COMMAND</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 463:</td> <td colspan="2" class="diff-lineno">Line 463:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>19930 pts/4    S      0:01 bash</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>19930 pts/4    S      0:01 bash</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>25740 pts/4    S      0:04  \_ vi processes.txt</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>25740 pts/4    S      0:04  \_ vi processes.txt</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>The "u" and "l" ps options</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>The "u" and "l" ps options <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>The <ins class="diffchange diffchange-inline"><span style="color:green"></ins>u<ins class="diffchange diffchange-inline"></span> </ins>or <ins class="diffchange diffchange-inline"><span style="color:green"></ins>l<ins class="diffchange diffchange-inline"></span> </ins>options can also be added to any combination of <ins class="diffchange diffchange-inline"><span style="color:green"></ins>a<ins class="diffchange diffchange-inline"></span> </ins>and <ins class="diffchange diffchange-inline"><span style="color:green"></ins>x<ins class="diffchange diffchange-inline"></span> </ins>in order to include more information about each process:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>The u or l options can also be added to any combination of a and x in order to include more information about each process:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps au</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps au</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>USER      PID %CPU %MEM  VSZ  RSS TTY      STAT START  TIME COMMAND</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>USER      PID %CPU %MEM  VSZ  RSS TTY      STAT START  TIME COMMAND</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 475:</td> <td colspan="2" class="diff-lineno">Line 475:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>agriffis  434  0.0  0.0  1008    4 tty1    S    2001  0:00 /bin/sh /usr/X</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>agriffis  434  0.0  0.0  1008    4 tty1    S    2001  0:00 /bin/sh /usr/X</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>chouser    927  0.0  0.0  2540  96 pts/1    S    2001  0:00 bash</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>chouser    927  0.0  0.0  2540  96 pts/1    S    2001  0:00 bash</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps al</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps al</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   F  UID  PID  PPID PRI  NI  VSZ  RSS WCHAN  STAT TTY        TIME COMMAND</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   F  UID  PID  PPID PRI  NI  VSZ  RSS WCHAN  STAT TTY        TIME COMMAND</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 483:</td> <td colspan="2" class="diff-lineno">Line 484:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>000  1001  434  403  9  0  1008    4 wait4  S    tty1      0:00 /bin/sh</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>000  1001  434  403  9  0  1008    4 wait4  S    tty1      0:00 /bin/sh</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>000  1000  927  652  9  0  2540  96 wait4  S    pts/1      0:00 bash</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>000  1000  927  652  9  0  2540  96 wait4  S    pts/1      0:00 bash</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Using top</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>Using top <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>If you find yourself running ps several times in a row, trying to watch things change, what you probably want is <ins class="diffchange diffchange-inline"><span style="color:green"></ins>top<ins class="diffchange diffchange-inline"></span></ins>. <ins class="diffchange diffchange-inline"><span style="color:green"></ins>top<ins class="diffchange diffchange-inline"></span> </ins>displays a continuously updated process listing, along with some useful summary information:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>If you find yourself running ps several times in a row, trying to watch things change, what you probably want is top. top displays a continuously updated process listing, along with some useful summary information:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ top</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ top</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>  10:02pm  up 19 days,  6:24,  8 users,  load average: 0.04, 0.05, 0.00</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>  10:02pm  up 19 days,  6:24,  8 users,  load average: 0.04, 0.05, 0.00</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 500:</td> <td colspan="2" class="diff-lineno">Line 501:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   652 chouser  11  0 12016 8840  1604 S      0  0.5  3.4  3:52 gnome-termin</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   652 chouser  11  0 12016 8840  1604 S      0  0.5  3.4  3:52 gnome-termin</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   641 chouser    9  0  2936 2808  1416 S      0  0.1  1.0  2:13 sawfish</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   641 chouser    9  0  2936 2808  1416 S      0  0.1  1.0  2:13 sawfish</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>nice</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>nice <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Each processes has a priority setting that Linux uses to determine how CPU timeslices are shared. You can set the priority of a process by starting it with the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>nice<ins class="diffchange diffchange-inline"></span> </ins>command:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Each processes has a priority setting that Linux uses to determine how CPU timeslices are shared. You can set the priority of a process by starting it with the nice command:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ nice -n 10 oggenc /tmp/song.wav</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ nice -n 10 oggenc /tmp/song.wav</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">Since the priority setting is called <span style="color:green">nice</span>, it should be easy to remember that a higher value will be nice to other processes, allowing them to get priority access to the CPU. By default, processes are started with a setting of 0, so the setting of 10 above means oggenc will readily give up the CPU to other processes. Generally, this means that oggenc will allow other processes to run at their normal speed, regardless of how CPU-hungry oggenc happens to be. You can see these niceness levels under the NI column in the ps and top listings above.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">Since the priority setting is called nice, it should be easy to remember that a higher value will be nice to other processes, allowing them to get priority access to the CPU. By default, processes are started with a setting of 0, so the setting of 10 above means oggenc will readily give up the CPU to other processes. Generally, this means that oggenc will allow other processes to run at their normal speed, regardless of how CPU-hungry oggenc happens to be. You can see these niceness levels under the NI column in the ps and top listings above.</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>renice <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>renice</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>The <ins class="diffchange diffchange-inline"><span style="color:green"></ins>nice<ins class="diffchange diffchange-inline"></span> </ins>command can only change the priority of a process when you start it. If you want to change the niceness setting of a running process, use <ins class="diffchange diffchange-inline"><span style="color:green"></ins>renice<ins class="diffchange diffchange-inline"></span></ins>:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>The nice command can only change the priority of a process when you start it. If you want to change the niceness setting of a running process, use renice:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps l 641</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ ps l 641</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   F  UID  PID  PPID PRI  NI  VSZ  RSS WCHAN  STAT TTY        TIME COMMAND</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   F  UID  PID  PPID PRI  NI  VSZ  RSS WCHAN  STAT TTY        TIME COMMAND</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 520:</td> <td colspan="2" class="diff-lineno">Line 521:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   F  UID  PID  PPID PRI  NI  VSZ  RSS WCHAN  STAT TTY        TIME COMMAND</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>   F  UID  PID  PPID PRI  NI  VSZ  RSS WCHAN  STAT TTY        TIME COMMAND</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>000  1000  641    1  9  10  5876 2808 do_sel S    ?          2:14 sawfish</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>000  1000  641    1  9  10  5876 2808 do_sel S    ?          2:14 sawfish</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Text processing</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">== </ins>Text processing <ins class="diffchange diffchange-inline">==</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">Redirection revisited</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== Redirection revisited ===</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Earlier in this tutorial series, we saw an example of how to use the > operator to redirect the output of a command to a file, as follows:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Earlier in this tutorial series, we saw an example of how to use the > operator to redirect the output of a command to a file, as follows:</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>  </table>

Rh1 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4111&oldid=prev Rh1 at 02:52, 22 March 2011 2011-03-22T02:52:19Z

<p></p> <table class='diff diff-contentalign-left'> <col class='diff-marker' /> <col class='diff-content' /> <col class='diff-marker' /> <col class='diff-content' /> <tr style='vertical-align: top;'> <td colspan='2' style="background-color: white; color:black;">← Older revision</td> <td colspan='2' style="background-color: white; color:black;">Revision as of 02:52, 22 March 2011</td> </tr><tr><td colspan="2" class="diff-lineno">Line 349:</td> <td colspan="2" class="diff-lineno">Line 349:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>=== Staring xeyes ===</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>=== Staring xeyes ===</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">{{fancynote|You may need to install xeyes on your system first. Consult your distro's documentation for instructions on installing}}</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>To learn about process control, we first need to start a process. Make sure that you have X running and execute the following command:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>To learn about process control, we first need to start a process. Make sure that you have X running and execute the following command:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ xeyes -center red</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ xeyes -center red</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>You will notice that an xeyes window pops up, and the red eyeballs follow your mouse around the screen. You may also notice that you don't have a new prompt in your terminal.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>You will notice that an xeyes window pops up, and the red eyeballs follow your mouse around the screen. You may also notice that you don't have a new prompt in your terminal.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">Stopping a process</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== Stopping a process ===</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>To get a prompt back, you could type Control-C (often written as Ctrl-C or ^C):</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>To get a prompt back, you could type Control-C (often written as Ctrl-C or ^C):</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>You get a new bash prompt, but the xeyes window disappeared. In fact, the entire process has been killed. Instead of killing it with Control-C, we could have just stopped it with Control-Z:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>You get a new bash prompt, but the xeyes window disappeared. In fact, the entire process has been killed. Instead of killing it with Control-C, we could have just stopped it with Control-Z:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ xeyes -center red</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ xeyes -center red</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Control-Z</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Control-Z</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]+  Stopped                xeyes -center red</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]+  Stopped                xeyes -center red</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>This time you get a new bash prompt, and the xeyes windows stays up. If you play with it a bit, however, you will notice that the eyeballs are frozen in place. If the xeyes window gets covered by another window and then uncovered again, you will see that it doesn't even redraw the eyes at all. The process isn't doing anything. It is, in fact, "Stopped."</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>This time you get a new bash prompt, and the xeyes windows stays up. If you play with it a bit, however, you will notice that the eyeballs are frozen in place. If the xeyes window gets covered by another window and then uncovered again, you will see that it doesn't even redraw the eyes at all. The process isn't doing anything. It is, in fact, "Stopped."</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">fg and bg</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;"></del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">To get the process "un-stopped" and running again, we can bring it to the foreground with the bash built-in fg:</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== fg and bg ===</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">To get the process "un-stopped" and running again, we can bring it to the foreground with the bash built-in <span style="color:green">fg</span>:</ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ fg</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ fg</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>(test it out, then stop the process again)</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>(test it out, then stop the process again)</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 375:</td> <td colspan="2" class="diff-lineno">Line 377:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]+  Stopped                xeyes -center red</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]+  Stopped                xeyes -center red</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Now continue it in the background with the bash built-in bg:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Now continue it in the background with the bash built-in <ins class="diffchange diffchange-inline"><span style="color:green"></ins>bg<ins class="diffchange diffchange-inline"></span></ins>:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ bg</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ bg</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]+ xeyes -center red &</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]+ xeyes -center red &</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Great! The xeyes process is now running in the background, and we have a new, working bash prompt.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Great! The xeyes process is now running in the background, and we have a new, working bash prompt.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">Using "&"</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== Using "&" ===</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>If we wanted to start xeyes in the background from the beginning (instead of using Control-Z and bg), we could have just added an "&" (ampersand) to the end of xeyes command line:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>If we wanted to start xeyes in the background from the beginning (instead of using Control-Z and bg), we could have just added an "&" (ampersand) to the end of xeyes command line:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ xeyes -center blue &</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ xeyes -center blue &</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2] 16224</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2] 16224</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Multiple background processes</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>Multiple background processes <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>Now we have both a red and a blue xeyes running in the background. We can list these jobs with the bash built-in <ins class="diffchange diffchange-inline"><span style="color:green"></ins>jobs<ins class="diffchange diffchange-inline"></span></ins>:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Now we have both a red and a blue xeyes running in the background. We can list these jobs with the bash built-in jobs:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]- 16217 Running                xeyes -center red &</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]- 16217 Running                xeyes -center red &</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Running                xeyes -center blue &</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Running                xeyes -center blue &</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">The numbers in the left column are the job numbers bash assigned when they were started. Job 2 has a + (plus) to indicate that it's the "current job," which means that typing <span style="color:green">fg</span> will bring it to the foreground. You could also foreground a specific job by specifying its number; for example, <span style="color:green">fg 1</span> would make the red xeyes the foreground task. The next column is the process id or pid, included in the listing courtesy of the -l option to jobs. Finally, both jobs are currently "Running," and their command lines are listed to the right.</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del class="diffchange diffchange-inline">The numbers in the left column are the job numbers bash assigned when they were started. Job 2 has a + (plus) to indicate that it's the "current job," which means that typing fg will bring it to the foreground. You could also foreground a specific job by specifying its number; for example, fg 1 would make the red xeyes the foreground task. The next column is the process id or pid, included in the listing courtesy of the -l option to jobs. Finally, both jobs are currently "Running," and their command lines are listed to the right.</del></div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>Introducing signals <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Introducing signals</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div>To kill, stop, or continue processes, Linux uses a special form of communication called "signals." By sending a certain signal to a process, you can get it to terminate, stop, or do other things. This is what you're actually doing when you type Control-C, Control-Z, or use the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>bg<ins class="diffchange diffchange-inline"></span> </ins>or <ins class="diffchange diffchange-inline"><span style="color:green"></ins>fg<ins class="diffchange diffchange-inline"></span> </ins>built-ins -- you're using bash to send a particular signal to the process. These signals can also be sent using the <ins class="diffchange diffchange-inline"><span style="color:green"></ins>kill<ins class="diffchange diffchange-inline"></span> </ins>command and specifying the pid (process id) on the command line:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>To kill, stop, or continue processes, Linux uses a special form of communication called "signals." By sending a certain signal to a process, you can get it to terminate, stop, or do other things. This is what you're actually doing when you type Control-C, Control-Z, or use the bg or fg built-ins -- you're using bash to send a particular signal to the process. These signals can also be sent using the kill command and specifying the pid (process id) on the command line:</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ kill -s SIGSTOP 16224</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ kill -s SIGSTOP 16224</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]- 16217 Running                xeyes -center red &</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]- 16217 Running                xeyes -center red &</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Stopped (signal)        xeyes -center blue</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Stopped (signal)        xeyes -center blue</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>As you can see, kill doesn't necessarily "kill" a process, although it can. Using the "-s" option, kill can send any signal to a process. Linux kills, stops or continues processes when they are sent the SIGINT, SIGSTOP, or SIGCONT signals respectively. There are also other signals that you can send to a process; some of these signals may be interpreted in an application-dependent way. You can learn what signals a particular process recognizes by looking at its man-page and searching for a SIGNALS section.</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>As you can see, kill doesn't necessarily "kill" a process, although it can. Using the "-s" option, kill can send any signal to a process. Linux kills, stops or continues processes when they are sent the SIGINT, SIGSTOP, or SIGCONT signals respectively. There are also other signals that you can send to a process; some of these signals may be interpreted in an application-dependent way. You can learn what signals a particular process recognizes by looking at its man-page and searching for a SIGNALS section.</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div><del style="color: red; font-weight: bold; text-decoration: none;">SIGTERM and SIGINT</del></div></td><td colspan="2"> </td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;">=== SIGTERM and SIGINT ===</ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>If you want to kill a process, you have several options. By default, kill sends SIGTERM, which is not identical to SIGINT of Control-C fame, but usually has the same results:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>If you want to kill a process, you have several options. By default, kill sends SIGTERM, which is not identical to SIGINT of Control-C fame, but usually has the same results:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ kill 16217</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ kill 16217</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]- 16217 Terminated              xeyes -center red</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1]- 16217 Terminated              xeyes -center red</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Stopped (signal)        xeyes -center blue</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Stopped (signal)        xeyes -center blue</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>The big kill</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>The big kill <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Processes can ignore both SIGTERM and SIGINT, either by choice or because they are stopped or somehow "stuck." In these cases it may be necessary to use the big hammer, the SIGKILL signal. A process cannot ignore SIGKILL:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>Processes can ignore both SIGTERM and SIGINT, either by choice or because they are stopped or somehow "stuck." In these cases it may be necessary to use the big hammer, the SIGKILL signal. A process cannot ignore SIGKILL:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ kill 16224</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ kill 16224</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td></tr> <tr><td colspan="2" class="diff-lineno">Line 428:</td> <td colspan="2" class="diff-lineno">Line 430:</td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ jobs -l</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Interrupt              xeyes -center blue</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[2]+ 16224 Interrupt              xeyes -center blue</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>nohup</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>nohup <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The terminal where you start a job is called the job's controlling terminal. Some shells (not bash by default), will deliver a SIGHUP signal to backgrounded jobs when you logout, causing them to quit. To protect processes from this behavior, use the nohup when you start the process:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The terminal where you start a job is called the job's controlling terminal. Some shells (not bash by default), will deliver a SIGHUP signal to backgrounded jobs when you logout, causing them to quit. To protect processes from this behavior, use the nohup when you start the process:</div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline"><pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ nohup make &</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ nohup make &</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1] 15632</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>[1] 15632</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ exit</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>$ exit</div></td></tr> <tr><td colspan="2"> </td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins style="color: red; font-weight: bold; text-decoration: none;"></pre></ins></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div>Using ps to list processes</div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div><ins class="diffchange diffchange-inline">=== </ins>Using ps to list processes <ins class="diffchange diffchange-inline">===</ins></div></td></tr> <tr><td class='diff-marker'>−</td><td style="background: #ffa; color:black; font-size: smaller;"><div> </div></td><td class='diff-marker'>+</td><td style="background: #cfc; color:black; font-size: smaller;"><div></div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The jobs command we were using earlier only lists processes that were started from your bash session. To see all the processes on your system, use ps with the a and x options together:</div></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"><div>The jobs command we were using earlier only lists processes that were started from your bash session. To see all the processes on your system, use ps with the a and x options together:</div></td></tr> <tr><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td><td class='diff-marker'> </td><td style="background: #eee; color:black; font-size: smaller;"></td></tr>  </table>

Rh1 http://www.funtoo.org/index.php?title=Linux_Fundamentals,_Part_2&diff=4110&oldid=prev Rh1 at 23:18, 19 March 2011 2011-03-19T23:18:49Z

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Rh1