- display information about currently logged-in users
w [-hlsuw] [user]
The w command displays a summary of the current activity on the system, including what each user is doing. The heading line shows the current time, the length of time the system has been up, the number of users logged into the system, and the average number of jobs in the run queue over the last 1, 5 and 15 minutes.
The fields displayed are: the user's login name, the name of the tty the user is on, the time of day the user logged on (in hours:minutes), the idle time—that is, the number of minutes since the user last typed anything (in hours:minutes), the CPU time used by all processes and their children on that terminal (in minutes:seconds), the CPU time used by the currently active processes (in minutes:seconds), and the name and arguments of the current process.
The following options are supported:
Suppresses the heading.
Produces a long form of output, which is the default.
Produces 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.
Produces the heading line which shows the current time, the length of time the system has been up, the number of users logged into the system, and the average number of jobs in the run queue over the last 1, 5 and 15 minutes.
Produces a long form of output, which is also the same as the default.
Name of a particular user for whom login information is displayed. If specified, output is restricted to that user.
示例 1 Sample Output From the w Command
example% w 10:54am up 27 day(s), 57 mins, 1 user, load average: 0.28, 0.26, 0.22 User tty login@ idle JCPU PCPU what ralph console 7:10am 1 10:05 4:31 w
See environ(5) for descriptions of the following environment variables that affect the execution of w: LC_CTYPE, LC_MESSAGES, and LC_TIME.
user and accounting information
See attributes(5) for descriptions of the following attributes:
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, 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.
w does not know about the conventions for detecting background jobs. It will sometimes find a background job instead of the right one.