man who

WHO(1)                           User Commands                          WHO(1)

NAME
       who - show who is logged on

SYNOPSIS
       who [OPTION]... [ FILE | ARG1 ARG2 ]

DESCRIPTION
       Print information about users who are currently logged in.

       -a, --all
              same as -b -d --login -p -r -t -T -u

       -b, --boot
              time of last system boot

       -d, --dead
              print dead processes

       -H, --heading
              print line of column headings

       -l, --login
              print system login processes

       --lookup
              attempt to canonicalize hostnames via DNS

       -m     only hostname and user associated with stdin

       -p, --process
              print active processes spawned by init

       -q, --count
              all login names and number of users logged on

       -r, --runlevel
              print current runlevel

       -s, --short
              print only name, line, and time (default)

       -t, --time
              print last system clock change

       -T, -w, --mesg
              add user’s message status as +, - or ?

       -u, --users
              list users logged in

       --message
              same as -T

       --writable
              same as -T

       --help display this help and exit

       --version
              output version information and exit

       If  FILE is not specified, use /var/run/utmp.  /var/log/wtmp as FILE is
       common.  If ARG1 ARG2 given, -m presumed: ‘am i’  or  ‘mom  likes’  are
       usual.

AUTHOR
       Written by Joseph Arceneaux, David MacKenzie, and Michael Stone.

REPORTING BUGS
       Report who bugs to bug-coreutils@gnu.org
       GNU coreutils home page: <http://www.gnu.org/software/coreutils/>
       General help using GNU software: <http://www.gnu.org/gethelp/>
       Report who translation bugs to <http://translationproject.org/team/>

COPYRIGHT
       Copyright  ©  2010  Free Software Foundation, Inc.  License GPLv3+: GNU
       GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free  to  change  and  redistribute  it.
       There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
       The  full  documentation for who is maintained as a Texinfo manual.  If
       the info and who programs are properly installed at your site, the com-
       mand

              info coreutils 'who invocation'

       should give you access to the complete manual.

GNU coreutils 8.4                 March 2017                            WHO(1)