linux - who (1)

       who - show who is logged on

       who  [-imqsuwHT]  [--count]  [--idle] [--heading] [--help]
       [--message] [--mesg] [--version] [--writable]  [file]  [am
       i]

       This  manual  page  documents  the GNU version of who.  If
       given no non-option arguments, who  prints  the  following
       information for each user currently logged on:

              login name
              terminal line
              login time
              remote hostname or X display

       If given one non-option argument, who uses that instead of
       /etc/utmp as the name of the file containing the record of
       users  logged on.  /etc/wtmp is commonly given as an argu-
       ment to who to look at who has previously logged on.

       If given two non-option arguments,  who  prints  only  the
       entry  for  the user running it (determined from its stan-
       dard input), preceded by the hostname.  Traditionally, the
       two arguments given are `am i', as in `who am i'.

   OPTIONS
       -m     Same as `who am i'.

       -q, --count
              Print  only the login names and the number of users
              logged on.  Overrides all other options.

       -s     Ignored; for compatibility with other  versions  of
              who.

       -i, -u, --idle
              After the login time, print the number of hours and
              minutes that the user has been idle.  `.' means the
              user  was  active  in last minute.  `old' means the
              user was idle for more than 24 hours.

       -H, --heading
              Print a line of column headings.

       -w, -T, --mesg, --message, --writable
              Like -s, plus after the login name print a  charac-
              ter indicating the user's message status:

              +      allowing write messages
              ?      cannot find terminal device

       --help Print  a  usage message on standard output and exit
              successfully.

       --version
              Print version information on standard  output  then
              exit successfully.