NAME
w - who is on and what they are doing

SYNOPSIS
w [ -hls ] [ user ]

DESCRIPTION
W prints a summary of the current activity on the system, including
what each user is doing. The heading line shows the current time
of day, how long the system has been up, 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
minutes.

The fields output are: the user’s login name, the name of the tty
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,
the CPU time used by all processes and their children on that
terminal, the CPU time used by the currently active processes, the
name and arguments of the current process.

The -h flag suppresses the heading. The -s flag asks for a short
form of output. In the short form, the tty is abbreviated, the
login time and cpu times are left off, as are the arguments to
commands. -l gives the long output, which is the default. The -f
option suppresses the "from" field.

If a user name is included, the output will be restricted to that
user.

FILES
/etc/utmp
/dev/kmem

SEE ALSO
who(1), finger(1), ps(1)

AUTHOR
Mark Horton

BUGS
The notion of the "current process" is muddy. The current
algorithm is "the highest numbered process on the terminal that is
not ignoring interrupts, or, if there is none, the highest numbered
process on the terminal". 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
"-".)

CPU time is 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.

W does not know about the new conventions for detection of
background jobs. It will sometimes find a background job instead
of the right one.