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WHO(1)                    BSD General Commands Manual                   WHO(1)

NAME
     who -- display who is on the system

SYNOPSIS
     who [-HmqsTu] [am I] [file]

DESCRIPTION
     The who utility displays information about currently logged in users.  By default, this includes the
     login name, tty name, date and time of login and remote hostname if not local.

     The options are as follows:

     -H      Write column headings above the output.

     -m      Show information about the terminal attached to standard input only.

     -q      ``Quick mode'': List the names and number of logged in users in columns.  All other command
             line options are ignored.

     -s      Show the name, line and time fields only.  This is the default.

     -T      Indicate whether each user is accepting messages.  One of the following characters is written:

             +  User is accepting messages.
             -  User is not accepting messages.
             ?  An error occurred.

     -u      Show idle time for each user in hours and minutes as hh:mm, `.' if the user has been idle less
             than a minute, and ``old'' if the user has been idle more than 24 hours.  Additionally, display
             the PID of the user's login process.

     am I    Equivalent to -m.

     By default, who gathers information from the file /var/run/utmpx.  An alternate file may be specified.

LEGACY DESCRIPTION
     In legacy mode, -u does not display the PID of the user's login process.

     For more information about legacy mode, see compat(5).

ENVIRONMENT
     The COLUMNS, LANG, LC_ALL and LC_TIME environment variables affect the execution of who as described in
     environ(7).

FILES
     /var/run/utmpx

DIAGNOSTICS
     The who utility exits 0 on success, and >0 if an error occurs.

SEE ALSO
     last(1), users(1), w(1), compat(5), utmpx(5)

STANDARDS
     The who utility conforms to IEEE Std 1003.1-2001 (``POSIX.1'').

HISTORY
     A who command appeared in Version 1 AT&T UNIX.

BSD                               May 8, 2002                              BSD