w.1

<B>Digital的Unix操作系统VAX 4.2源码</B>

.\" SCCSID: @(#)w.1	8.1	9/11/90
.TH w 1
.SH Name
w \- display who is logged in and what they are doing
.SH Syntax
.B w
[ \fIoptions\fR ] [\|\fIuser\fR\|]
.SH Description
.NXR "w command" 
The
.PN w
command
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.
.PP
The fields output are:
.NXR "w command" "output fields"
.NXR "terminal" "showing name"
.NXR "system" "showing login time"
.NXR "date" "showing"
.NXR "time" "showing"
.NXR "system" "showing uptime"
.NXR "system" "showing users"
.NXR "system" "showing run queue average"
.NXR "system" "showing user activity"
.NXR "process" "printing status"
.nf
The users login name
The name of the tty the user is on
The host from which the user is logged in
The time of day the user logged on
The number of minutes 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
.fi
.SH Options
.NXR "w command" "options"
.IP \fB\-d\fR 0.3i
Outputs debug information.
.IP \fB\-f\fR 0.3i
Suppresses the `from' field.
.IP \fB\-h\fR 0.3i
Suppresses the normal header from the output.  
.IP \fB\-l\fR 0.3i
Displays information in long format (default).  
.IP \fB\-s\fR 0.3i
Displays information in short format.  
In the short form, the tty is abbreviated, the login time and cpu times
are left off, as are the arguments to commands.
.IP \fB\-u\fR 0.3i
Outputs the same information as the 
.PN uptime
command.
.IP
If a
.I user
name is included,
the output will be restricted to that user.
.SH Restrictions
.NXR "w command" "restricted"
The notion of the ``current process'' is unclear.
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,
.PN w
prints ``\-''.)
.PP
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.
.PP
Background processes are not shown, even though they account for
much of the load on the system.
.PP
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.
.PP
The
.PN w
command does not know about conventions
for detection of background jobs.
It will sometimes find a background job instead of the right one.
.SH Files
.ta 1i
/etc/utmp
.br
/dev/kmem
.br
/dev/drum
.SH See Also
finger(1), ps(1), who(1)