W(1) BSD Reference Manual W(1)
w - who present users are and what they are doing
w [-hin] [-M core] [-N system] [user]
The w utility prints a summary of the current activity on the system, in-
cluding what each user is doing. The first line displays the current
time of day, how long the system has been running, the number of users
logged into the system, and the load averages. The load average numbers
give the number of jobs in the run queue averaged over 1, 5 and 15 min-
The fields output are the user's login name, the name of the terminal the
user is on, the host from which the user is logged in, the time the user
logged on, the time since the user last typed anything, and the name and
arguments of the current process.
The options are as follows:
-h Suppress the heading.
-i Output is sorted by idle time.
-M Extract values associated with the name list from the specified
core instead of the default ``/dev/kmem''.
-N Extract the name list from the specified system instead of the
-n Show network addresses as numbers (normally w interprets address-
es and attempts to display them symbolically).
If a user name is specified, the output is restricted to that user.
/var/run/utmp list of users on the system
who(1), finger(1), ps(1), uptime(1),
The notion of the ``current process'' is muddy. The current algorithm is
``the highest numbered process on the terminal that is not ignoring in-
terrupts, or, if there is none, the highest numbered process on the ter-
minal''. This fails, for example, in critical sections of programs like
the shell and editor, or when faulty programs running in the background
fork and fail to ignore interrupts. (In cases where no process can be
found, w prints ``-''.)
The CPU time is only an estimate, in particular, if someone leaves a
background process running after logging out, the person currently on
that terminal is ``charged'' with the time.
Background processes are not shown, even though they account for much of
the load on the system.
Sometimes processes, typically those in the background, are printed with
null or garbaged arguments. In these cases, the name of the command is
printed in parentheses.
The w utility does not know about the new conventions for detection of
background jobs. It will sometimes find a background job instead of the
The -f, -l, -s, and -w flags are no longer supported.
The w command appeared in UNIX3.0.
4th Berkeley Distribution June 6, 1993 2