NAME
who —
display who is on the system
SYNOPSIS
who |
[-abHmqsTu] [am I]
[file] |
DESCRIPTION
The who utility displays information about
currently logged in users. By default, this includes the login name, tty
name, date and time of login and remote hostname if not local.
The options are as follows:
-a- Equivalent to
-bTu, with the exception that output is not restricted to the time and date of the last system reboot. -b- Write the time and date of the last system reboot.
-H- Write column headings above the output.
-m- Show information about the terminal attached to standard input only.
-q- “Quick mode”: List the names and number of logged in users in columns. All other command line options are ignored.
-s- Show the name, line and time fields only. This is the default.
-T- Indicate whether each user is accepting messages. One of the following
characters is written:
+- User is accepting messages.
-- User is not accepting messages.
?- An error occurred.
-u- Show idle time for each user in hours and minutes as
hh:mm,
‘
.’ if the user has been idle less than a minute, and “old” if the user has been idle more than 24 hours. am I- Equivalent to
-m.
By default, who gathers information from
the file /var/run/utmpx. An alternate
file may be specified which is usually
/var/log/utx.log (or
/var/log/utx.log.[0-6] depending on site policy as
utx.log can grow quite large and daily versions may
or may not be kept around after compression by
ac(8)). The
utx.log file contains a record of every login,
logout, crash, shutdown and date change since
utx.log was last truncated or created.
If /var/log/utx.log is being used as the file, the user name may be empty or one of the special characters '|', '}' and '~'. Logouts produce an output line without any user name. For more information on the special characters, see getutxent(3).
ENVIRONMENT
The COLUMNS, LANG,
LC_ALL and LC_TIME
environment variables affect the execution of who as
described in environ(7).
FILES
- /var/run/utmpx
EXIT STATUS
The who utility exits 0 on success,
and >0 if an error occurs.
EXAMPLES
Show a brief summary of who is logged in:
$ who -q fernape root root # users = 3
Show who is logged in along with the line and time fields (without the headers):
$ who -s fernape ttyv0 Aug 26 16:23 root ttyv1 Aug 26 16:23 root ttyv2 Aug 26 16:23
Show information about the terminal attached to standard input:
$ who am i fernape Aug 26 16:24
Show time and date of the last system reboot, whether the users accept messages and the idle time for each of them:
$ who -a
- system boot Aug 26 16:23 .
fernape - ttyv0 Aug 26 16:23 .
root - ttyv1 Aug 26 16:23 .
root - ttyv2 Aug 26 16:23 .
Same as above but showing headers:
$ who -aH
NAME S LINE TIME IDLE FROM
- system boot Aug 26 16:23 .
fernape - ttyv0 Aug 26 16:23 .
root - ttyv1 Aug 26 16:23 00:01
root - ttyv2 Aug 26 16:23 00:01
SEE ALSO
STANDARDS
The who utility conforms to
IEEE Std 1003.1-2001 (“POSIX.1”).
HISTORY
A who command appeared in
Version 1 AT&T UNIX.