This package contains utilities to modify users' passwords, add or delete users and groups, and the like. We're not going to explain what 'password shadowing' means. A full explanation can be found in the doc/HOWTO file within the unpacked Shadow source tree. There's one thing to keep in mind if you decide to use Shadow support: programs that need to verify passwords (for example xdm, ftp daemons, pop3 daemons) need to be 'shadow-compliant', that is they need to be able to work with shadowed passwords. To enable shadowed passwords, run the following command: /usr/sbin/pwconv And to enable shadowed group passwords, run the following command: /usr/sbin/grpconv Under normal circumstances, you won't have created any passwords yet. However, if returning to this section to enable shadowing, you should reset any current user passwords with the passwd command or any group passwords with the gpasswd command.