who(1) who(1)
NAME
who - who is on the system
SYNOPSIS
who [-uTlmHpdbrtas] [file]
who -q [-n x] [file]
who am i
who am I
DESCRIPTION
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/utmp file to
obtain its information. If file is given, that file (which
must be in utmp(4) format) is examined. Usually, file will be
/var/adm/wtmp, which contains a history of all the logins
since the file was last created.
who with 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]
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, below.
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. 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.
Copyright 1994 Novell, Inc. Page 1
who(1) who(1)
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.
-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 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 Like who am i , this option lists information for the
invoking user only. who -m is equivalent to who am i ,
with the exception that -m can be used in conjunction
with other options.
-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 except -n 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 processes that have expired and
have not been respawned by init. These include
processes for lines on which the user has logged out.
The exit field appears for dead processes and contains
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who(1) who(1)
the termination and exit values [as returned by
wait(2)], of the dead process. This can be useful in
determining why a process terminated. The utmp entry
for a dead process remains only until the utmp entry is
used for another process.
-b This option indicates the time and date of the last
reboot.
-r This option shows the current run-level of the init
process, the number of times previously in that run-
level, and the prior run-level 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/utmp or the named file
with the -ulpdbrtTH options turned on.
-s This option is the default and lists only the name,
line, and time fields.
-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 is ignored except when used with
-q.
Files
/var/adm/wtmp
/etc/inittab
/var/adm/utmp
/usr/lib/locale/locale/LC_MESSAGES/uxcore.abi
language-specific message file [See LANG in environ(5).]
REFERENCES
date(1), init(1M), inittab(4), login(1), mesg(1), su(1M),
utmp(4), wait(2)
Copyright 1994 Novell, Inc. Page 3