pass is a password manager following the Unix philosophy.
From the website:
With pass, each password lives inside of a gpg encrypted file whose filename is the title of the website or resource that requires the password. These encrypted files may be organized into meaningful folder hierarchies, copied from computer to computer, and, in general, manipulated using standard command line file management utilities.
pass makes managing these individual password files extremely easy. All passwords live in ~/.password-store, and pass provides some nice commands for adding, editing, generating, and retrieving passwords. It is a very short and simple shell script. It's capable of temporarily putting passwords on your clipboard and tracking password changes using git.
You can edit the password store using ordinary unix shell commands alongside the pass command. There are no funky file formats or new paradigms to learn. There is bash completion so that you can simply hit tab to fill in names and commands, as well as completion for zsh and fish available in the completion folder. The community has even produced a GUI client, an iOS app, a Firefox plugin, a dmenu script, and even an emacs package.
You can install 'pass' the usual way:
# emerge -a pass
However if you want the features like zsh completion or dmenu script you should add some USe flags to configure pass to your needs.
If you have 'equery' installed you can check the all available USE flags including their description using:
# equery u pass
Soon the wiki will list the use flags of packages too!
For example if you want pass the abillity to import passwords form other other password managers you should add 'importers':
# echo "app-admin/pass importers" >> /etc/portage/package.use"