WHO(1)                               SysV                               WHO(1)



NAME
     who - who is on the system

SYNOPSIS
     who [ -bdHqstTu ] [ file ]

     who [ -bdHqstTu ] [ -a | -d | -n arg ]

     who am i

     who am I

DESCRIPTION
     who lists the name, terminal line, login time, elapsed time since
     activity occurred on the line, and the process-ID for each current UNIX
     system user.  It examines the /etc/utmp file, which is written at login
     time, to obtain its information.  If file is given, that file (which must
     be in utmp(4) format) is examined.  file is usually /etc/wtmp, which
     contains a history of all the logins since the file was last created.

     who with either the am i or am I option identifies the invoking user.

     The general format for output is:

          name [state] line time [idle] [pid] [comment] [exit]

     With options, who can list logins, logoffs, reboots, and changes to the
     system clock, as well as other processes spawned by the init process.

OPTIONS
     -a        Processes /etc/utmp or the named file for all nodes in the
               ring.

     -b        Indicates the time and date of the last reboot.

     -d        Display all nodes which have been booted diskless from the node
               specified.  The default is the node from which the command is
               executed.

     -fnodefile
               Specifies nodes for which /etc/utmp are processed.  nodefile
               should contain lines in the form: //nodename or [net.]nodeid,
               one per line.  A pound sign (#) in the first column causes that
               line to be treated as a comment.

     -H        Prints column headings above the regular output.

     -narg1 [ ,arg2 ]
               Specifies nodes for which /etc/utmp are processed.  arg lists
               the nodes to be processed, and should be in the form:
               //nodename or [net.]nodeid.  If more than one node is specified
               they should be either separated by commas or separated by
               whitespace and the entire argument in quotes.

     -q        Displays only the names and the number of users currently
               logged on.  When this option is used, all other options are
               ignored.

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

     -t        Indicates the last change to the system clock (via date(1)) by
               root.  See su(1).

     -T        The same as  -s except that the state of the terminal line is
               printed.  The state describes whether someone else can write to
               that terminal.  A + appears if the terminal is writable by
               anyone; a - appears if it is not.  root can write to all lines
               having a + or a - in the state field.  If a bad line is
               encountered, a ? is printed.

     -u        Lists only those users who are currently logged in.  name is
               the user's login name.  line is the name of the line as found
               in the directory /dev.  time is the time that the user logged
               in.

NOTES
     All options produce name, line, and time information except -q; only -T
     produces state information.

     After a shutdown to the single-user state, who returns a prompt; the
     reason is that since /etc/utmp is updated at login time and there is no
     login in single-user state, who cannot report accurately on this state.
     who am i, however, returns the correct information.

WARNINGS
     /etc/utmp can be an unreliable source of login information.  /etc/utmp is
     written by the most recently executed /bin/login, which is not
     necessarily the same as the current login.

FILES
     /etc/utmp
     /etc/wtmp

SEE ALSO
     date(1), login(1), init(1M), mesg(1), su(1M),
     getuid(2), wait(2), getpwuid(3C), utmp(4).