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

NAME
     who -- display who is logged in

SYNOPSIS
     who [-abdHlmpqrsTtu] [file]
     who am i

DESCRIPTION
     The who utility displays a list of all users currently logged on, showing
     for each user the login name, tty name, the date and time of login, and
     hostname if not local.

     Available options:

     -a    Same as -bdlprTtu.

     -b    Time of last system boot.

     -d    Print dead processes.

     -H    Write column headings above the regular output.

     -l    Print system login processes (unsupported).

     -m    Only print information about the current terminal.  This is the
           POSIX way of saying who am i.

     -p    Print active processes spawned by launchd(8) (unsupported).

     -q    ``Quick mode'': List only the names and the number of users cur-
           rently logged on.  When this option is used, all other options are
           ignored.

     -r    Print the current runlevel.  This is meaningless on Mac OS X.

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

     -T    Print a character after the user name indicating the state of the
           terminal line: `+' if the terminal is writable; `-' if it is not;
           and `?' if a bad line is encountered.

     -t    Print last system clock change (unsupported).

     -u    Print the idle time for each user, and the associated process ID.

     am I  Returns the invoker's real user name.

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

FILES
     /var/run/utmpx

SEE ALSO
     last(1), mesg(1), users(1), getuid(2), utmpx(5)

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

HISTORY
     A who utility appeared in Version 6 AT&T UNIX.

BSD                            January 17, 2007                            BSD