linux man page for 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

       --ips  print ips instead of hostnames. with --lookup, canonicalizes based on stored IP, if available, rather than stored hostname

       -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 (C) 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
       command

	      info coreutils 'who invocation'

       should give you access to the complete manual.

GNU coreutils 8.5						   February 2011							    WHO(1)