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).
