## User Database

A simple, local database of users and groups is, on UNIX computers,
stored in text files in the ‹/etc› directory. This database is
usually present even when it is supplemented by a network-based
database like LDAP (which is the case on ‹aisa› and on school
computers in general).

You can look at the files with a text editor or just ‹cat› them, and
quite easily understand the format from just looking. More details
can be found in ‹man 5 passwd›.

    $ cat /etc/passwd
    $ cat /etc/group

Next up: ‹getid.c›.
