NAME
who —
display who is logged in
SYNOPSIS
who |
[-abdHlmqrstTuv]
[file] |
DESCRIPTION
The
who utility displays a list of all users currently logged
on, showing for each user the login name, tty name, the date and time of
login, and hostname if not local.
Available options:
-
-
- -a
- Same as --bdlprTtuv.
-
-
- -b
- Time of last system boot.
-
-
- -d
- Print dead processes.
-
-
- -H
- Write column headings above the regular output.
-
-
- -l
- Print system login processes.
-
-
- -m
- Only print information about the current terminal. This is
the POSIX way of saying who am
i.
-
-
- -p
- Print active processes spawned by
init(8).
-
-
- -q
- “Quick mode”: List only the names and the
number of users currently logged on. When this option is used, all other
options are ignored.
-
-
- -r
- Print the current runlevel. Supported runlevels are:
-
-
d
(DEATH
)
- The system has halted.
-
-
s
(SINGLE_USER
)
- The system is running in single user mode.
-
-
r
(RUNCOM
)
- The system is executing /etc/rc.
-
-
t
(READ_TTYS
)
- The system is processing
/etc/ttys.
-
-
m
(MULTI_USER
)
- The system is running in multi-user mode.
-
-
T
(CLEAN_TTYS
)
- The system is in the process of stopping processes
associated with terminal devices.
-
-
c
(CATATONIA
)
- The system is in the process of shutting down and will
not create new processes.
-
-
- -s
- List only the name, line and time fields. This is the
default.
-
-
- -T
- Print a character after the user name indicating the state
of the terminal line: ‘+’ if the terminal is writable;
‘-’ if it is not; and ‘?’ if a bad line is
encountered.
-
-
- -t
- Print last system clock change.
-
-
- -u
- Print the idle time for each user, and the associated
process ID.
-
-
- -v
- When printing of more information is requested with
-u, this switch can be used to also printed process
termination signals, process exit status, session id for windowing and the
type of the entry, see documentation of ut_type in
getutxent(3).
-
-
- am
I
- Returns the invoker's real user name.
-
-
- file
- By default, who gathers information from
the file /var/run/utmpx. An alternative
file may be specified which is usually
/var/log/wtmpx (or /var/log/wtmp, or
/var/log/wtmpx.[0-6] or
/var/log/wtmp.[0-6] depending on site policy as
wtmpx can grow quite large and daily versions may or may
not be kept around after compression by
ac(8)). The
wtmpx and wtmp file contains a record
of every login, logout, crash, shutdown and date change since
wtmpx and wtmp were last truncated or
created.
If
/var/log/wtmpx or
/var/log/wtmp are 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
utmp(5).
FILES
- /var/run/utmp
-
- /var/run/utmpx
-
- /var/log/wtmp
-
- /var/log/wtmp.[0-6]
-
- /var/log/wtmpx
-
- /var/log/wtmpx.[0-6]
-
SEE ALSO
last(1),
mesg(1),
users(1),
getuid(2),
utmp(5),
utmpx(5)
STANDARDS
The
who utility is expected to conform to
IEEE Std 1003.2-1992 (“POSIX.2”).
HISTORY
A
who utility appeared in
Version 1
AT&T UNIX:
http://cm.bell-labs.com/cm/cs/who/dmr/pdfs/man14.pdf