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who(1)									who(1)

NAME    [Toc]    [Back]

     who - display who is on the system

SYNOPSIS    [Toc]    [Back]

     who [-mu] -s [-bHlprt] [ file ]

     who [-mTu]	[-abdHlprt] [ file ]

     who -qn x [ file ]

     who am i

     who am I

DESCRIPTION    [Toc]    [Back]

     who can list the user's name, terminal line, login	time, elapsed time
     since activity occurred on	the line, and the process ID of	the command
     interpreter (shell) for each current UNIX system user.  It	examines the
     /var/adm/utmpx file to obtain its information.  If	file is	given, that
     file (which must be in utmpx(4) format, and must have the filename	end
     with the letter x)	is examined.  Usually, file will be /var/adm/wtmpx,
     which contains a history of all the logins	since the file was last

     Note that who shows only users of ttys and	it does	not report any logged
     in	users who are simply running X applications from their desktop menus.

OPERANDS    [Toc]    [Back]

     who with the am i or am I operands	identifies the invoking	user.

OPTIONS    [Toc]    [Back]

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

     -u	   This	option lists only those	users who are currently	logged in.
	   The name is the user's login	name.  The line	is the name of the
	   line	as found in the	directory /dev.	 The time is the time that the
	   user	logged in.  The	idle column contains the number	of hours and
	   minutes since activity last occurred	on that	particular line
	   (roughly, the last time something was written on that 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 shell.  The 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, and so on.

									Page 1

who(1)									who(1)

     -T	   This	option is the same as the -u option, 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.

     -l	   This	option 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.

     -m	   This	option outputs only information	about the current terminal.

     -H	   This	option will print column headings above	the regular output.

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

     -p	   This	option 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 idle 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 not	been
	   respawned by	init.  The exit	field appears for dead processes and
	   contains the	termination and	exit values [as	returned by wait(2)],
	   of the dead process.	 This can be useful in determining why a
	   process terminated.

     -b	   This	option indicates the time and date of the last reboot.

     -r	   This	option indicates the current run-level of the init process.
	   In addition,	it produces the	current	state, the number of previous
	   times the system had	been in	the current state, and the previous
	   state under the idle, pid, and comment headings, respectively.

     -t	   This	option indicates the last change to the	system clock (via the
	   date	command) by root.  See su(1M).

     -a	   This	option processes /var/adm/utmpx	or the named file with all
	   options turned on.

     -s	   This	option is the default and lists	only the name, line, and time

     -n	x  This	option takes a numeric argument, x, which specifies the	number
	   of users to display per line.  x must be at least 1.	 The -n	option
	   must	be used	with -q.

									Page 2

who(1)									who(1)

     Note to privileged	users:	after a	shutdown to the	single-user state, who
     returns a prompt; the reason is that since	/var/adm/utmpx 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


     The following environment variables affect	the execution of who:

     LANG provide a default value for the internationalization variables that
	  are unset or null.  If LANG is unset or null the corresponding value
	  from the implementation-specific default locale will be used.	If any
	  of the internationalization variables	contains an invalid setting,
	  the utility will behave as if	none of	the variables had been

	  if set to a non-empty	string value, override the values of all the
	  other	internationalization variables.

	  determine the	locale for the interpretation of sequences of bytes of
	  text data as characters (for example,	single - as opposed to multibyte
 - characters in arguments).

	  determine the	locale that should be used to affect the format	and
	  contents of diagnostic messages written to standard error.

	  determine the	location of message catalogs for the processing	of

STDOUT    [Toc]    [Back]

     The general format	for output is:

	  name <b>[state<b>] line time <b>[idle<b>]	[pid<b>] [comment<b>]	[exit<b>]

     The name, line, and time information is produced by all options except
     -q; the state information is produced only	by -T; the idle	and pid
     information is produced only by -u, -l, and -T; and the comment and exit
     information is produced only by -a.  The information produced for -p, -d,
     and -r is explained during	the discussion of each option.

     The following format is used for the -T option:

	  "%s %c %s %s\n", <name>, <terminal state>, <terminal name>, <time of

     where <terminal state> is one of the following characters:

									Page 3

who(1)									who(1)

     +	  the terminal allows write access to other users

     -	  the terminal denies write access to other users

     ?	  the terminal write-access state cannot be determined

EXIT STATUS    [Toc]    [Back]

     The following exit	values are returned:
     0	 successful completion
     >0	 an error occurred

NOTES    [Toc]    [Back]

     w(1) and who(1) can report	different idle times for the same line.	 w
     will report the time elapsed since	input occurred,	while who will report
     the time elapsed since output occurred (roughly speaking).	 If there is a
     job running that produces output, the idle	times will differ between the
     two programs:

     babylon: who -Hu

     ttyd1	  Jul  6 10:37	 .     1955  alt console

     babylon: w

     User     tty from	      login@  idle   JCPU   PCPU  what root	d1
     10:37am  5:54     23     23  tail -f SYSLOG

FILES    [Toc]    [Back]

	  language-specific message file [See LANG on environ (5).]

SEE ALSO    [Toc]    [Back]

     date(1), login(1),	mesg(1), su(1M), init(1M), inittab(4), utmpx(4),

									PPPPaaaaggggeeee 4444
[ Back ]
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