WHO(1)                  System General Commands Manual                  WHO(1)

NAME
     who - display who is logged in

SYNOPSIS
     who [-mTuH] [file]
      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:

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

     -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.

     -u    Print the idle time for each user.

     -H    Write column headings above the regular output.

     am I  Returns the invoker's real user name.

     file  By default, who gathers information from the file /var/run/utmp.
           An alternative file may be specified which is usually /var/log/wtmp
           (or /var/log/wtmp.[0-6] depending on site policy as wtmp can grow
           quite large and daily versions may or may not be kept around after
           compression by ac(8)).  The wtmp file contains a record of every
           login, logout, crash, shutdown and date change since wtmp was last
           truncated or created.

     If /var/log/wtmp is being used as the file, the user name may be empty or
     one of the special characters '|', '}' and '~'.  Logouts produce an out-
     put line without any user name.  For more information on the special
     characters, see utmp(5).

FILES
     /var/run/utmp
     /var/log/wtmp
     /var/log/wtmp.[0-6]

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

STANDARDS
     The who utility is expected to conform to IEEE Std 1003.2-1992
     (``POSIX.2'').

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

BSD                            December 6, 1994                            BSD