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 who(1)								      who(1)




 NAME
      who - who is on the system

 SYNOPSIS
      who [-muTlHqpdbrtasAR] [file]

      who am i

      who am I

 DESCRIPTION
      The who command can list the user's name, terminal line, login time,
      elapsed time since input activity occurred on the line, the user's
      host name, and the process-ID of the command interpreter (shell) for
      each current system user.	 It examines the /etc/utmp file to obtain
      its information.	If file is given, that file is examined.  Usually,
      file is /var/adm/wtmp, which contains a history of all of the logins
      since the file was last created.

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

      Except for the default -s option, the general format for output
      entries is:

	   name [state] line time activity 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
	   -m		  Output only information about the current
			  terminal.  This option is equivalent to the am i
			  and am I options described above.

	   -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.
			  The time field indicates when the user logged in.

			  activity is the number of hours and minutes since
			  input activity last occurred on that particular
			  line.	 A dot (.) indicates that the terminal has
			  seen activity in the last minute and is therefore
			  ``current''.	If more than twenty-four hours have
			  elapsed or the line has not been used since boot
			  time, the entry is marked old.  This field is
			  useful when trying to determine whether a person
			  is working at the terminal or not.  The pid is the
			  process-ID of the user's login process.  The



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 who(1)								      who(1)




			  comment is the comment field associated with this
			  line as found in /etc/inittab (see inittab(4)).
			  This can contain information about where the
			  terminal is located, the telephone number of the
			  dataset, type of terminal if hard-wired, etc.	 If
			  no such information is found, then who prints, as
			  the comment, the user's host name as it was stored
			  in the /etc/utmp or named file.  Note that the
			  user's host name is printed instead of comments
			  from the /etc/inittab file if the -u option is
			  used in conjunction with the -R option.

	   -T		  Same as the -u option, except that the state of
			  the terminal line is printed.	 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.

			  (XPG4 only.) Only the following fields are
			  displayed: name state line time

	   -l		  Lists only those lines on which the system is
			  waiting for someone to login.	 The name field is
			  LOGIN in such cases.	Other fields are the same as
			  for user entries except that the state field does
			  not exist.

	   -H		  Prints column headings above the regular output.

	   -q		  A quick who, displaying only the names and the
			  number of users currently logged in.	When this
			  option is used, all other options are ignored.

	   -p		  Lists any other process which is currently active
			  and has been previously spawned by init.  The name
			  field is the name of the program executed by init
			  as found in /etc/inittab.  The state, line, and
			  activity fields have no meaning.  The comment
			  field shows the id field of the line from
			  /etc/inittab that spawned this process.  See
			  inittab(4).

	   -d		  This option displays all processes that have
			  expired and have not been respawned by init.	The
			  exit field appears for dead processes and contains
			  the termination and exit values of the dead
			  process (as returned by wait() - see wait(2)).
			  This can be useful in determining why a process
			  terminated.



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 who(1)								      who(1)




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

	   -r		  Indicates the current run-level of the init
			  process.  The last three fields contain the
			  current state of init, the number of times that
			  state has been previously entered, and the
			  previous state.  These fields are updated each
			  time init changes to a different run state.

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

	   -a		  Processes /etc/utmp or the named file with all
			  options turned on.

	   -s		  Default.  Lists only the name, line, and time
			  fields.

	   -A		  When the /var/adm/wtmp file is specified, this
			  option indicates when the accounting system was
			  turned on or off using the startup or shutacct
			  commands (see acctsh(1M)).  The name field is ..
			  The line field is acctg on, acctg off, or a reason
			  that was given as an option to the shutacct
			  command.  The time is the time that the on/off
			  activity occurred.

	   -R		  Displays the user's host name.  If the user is
			  logged in on a tty, who displays the string
			  returned from gethostname() (see gethostname(2)).
			  If the user is not logged in on a tty and the host
			  name stored in the /etc/utmp or named file has not
			  been truncated when stored (meaning that the
			  entire host name was stored with no loss of
			  information), it is displayed as it was stored.
			  Otherwise, the gethostbyaddr() function is called
			  with the internet address of the host (see
			  gethostent(3N)).  The host name returned by
			  gethostbyaddr() is displayed unless it returns an
			  error, in which case the truncated host name is
			  displayed.

      (XPG4 only.  The -s option can not be used with -d, -a or -T options.
      If -u option is used with -T, the idle time is added to the end of the
      -T format.)

 EXTERNAL INFLUENCES
    Environment Variables
      LANG determines the locale to use for the locale categories when both
      LC_ALL and the corresponding environment variable (beginning with LC_)
      do not specify a locale.	If LANG is not set or is set to the empty



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 who(1)								      who(1)




      string, a default of "C" (see lang(5)) is used.

      LC_CTYPE determines the locale for interpretation of sequences of
      bytes of text data as characters (e.g., single- verses multibyte
      characters in arguments and input files).

      LC_TIME determines the format and contents of date and time strings.

      LC_MESSAGES determines the language in which messages are displayed.

      If any internationalization variable contains an invalid setting, who
      behaves as if all internationalization variables are set to "C".	See
      environ(5).

    International Code Set Support
      Single- and multi-byte character code sets are supported.

 EXAMPLES
      Check who is logged in on the system:

	   who

      Check whether or not you can write to the terminal that another user
      is using:

	   who -T

      and look for a plus (+) after the user ID.

 AUTHOR
      who was developed by AT&T and HP.

 FILES
      /etc/inittab
      /etc/utmp
      /var/adm/wtmp

 SEE ALSO
      date(1), login(1), init(1M), mesg(1), su(1), gethostname(2), wait(2),
      gethostent(3N), inittab(4), utmp(4).

 STANDARDS CONFORMANCE
      who: SVID2, SVID3, XPG2, XPG3, XPG4, POSIX.2











 Hewlett-Packard Company	    - 4 -   HP-UX Release 11i: November 2000