id(1M)

NAME
     id - print the user name and ID, and group name and ID

SYNOPSIS
     id [-aM]
     id -G [-n] [user]
     id -g [-nr] [user]
     id -u [-nr] [user]

DESCRIPTION
     id displays the calling process's ID and name.  It also displays the
     group ID and name.  If the real and effective IDs do not match, both are
     printed.

     user The login name for which the information is to be reported.

     -a   Report all the groups to which the invoking process belongs.

     -g   Reports the effective group ID, using the format "%u\n".

     -G   Report all the groups to which the invoking process belongs.

     -M   If mandatory access control (MAC) is enabled the -M option reports
          the MAC label at which the invoking process is running.  If MAC is
          not enabled the option is ignored.

     -P   Reports the capability set of the invoking process.

     -n   Reports the name in the format "%s" instead of the numeric ID using
          the format "%u".

     -r   Reports the real ID instead of the effective ID.

     -u   Reports the effective user ID, using the format "%u\n".

FILES
     /etc/passwd                 system password file
     /etc/group                  system group file
     /etc/mac                    MAC label definition file

SEE ALSO
     logname(1), multgrps(1), newgrp(1), getgroups(2), getuid(2),
     setgroups(2), initgroups(3C).