who
who
The who
command is a Linux command that displays a list of users who are currently logged in to the system. It is a versatile command that can be used to quickly get a list of users who are logged in and what they are doing.
The who
command is used as follows:
who
The who
command will display the following information about each user who is logged in:
Username: The username of the user.
Terminal: The terminal that the user is logged into.
PID: The process ID of the user's shell.
Time: The time that the user logged in.
Idle: The amount of time that the user has been idle.
What: The command that the user is currently running.
For example, the following output from the who
command shows that the user johndoe
is logged into the terminal tty1
and has been idle for 2 minutes. The user is currently running the command vim
.
$ who
13:58:35 up 4 days, 3:42, 1 user, load average: 0.00, 0.01, 0.05
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
johndoe tty1 pts/0 13:56 2m 0.09s 0.09s vim
The who
command is a valuable tool for system administrators who need to monitor the activity of users on their system. It can also be used by users to see who else is logged in and what they are doing.
Here are some other options that can be used with the who
command:
-a
: This option will display all users who are logged in, including users who are logged in via remote terminals.-l
: This option will display additional information about each user, such as their real name and home directory.-r
: This option will display a list of users who are currently logged out, but who have not yet logged out completely.
The who
command is a powerful tool that can be used to get information about the users who are logged in to your system. It is a valuable tool for system administrators and users alike.
help
Usage: who [OPTION]... [ FILE | ARG1 ARG2 ]
Print information about users who are currently logged in.
-a, --all same as -b -d --login -p -r -t -T -u
-b, --boot time of last system boot
-d, --dead print dead processes
-H, --heading print line of column headings
--ips print ips instead of hostnames. with --lookup,
canonicalizes based on stored IP, if available,
rather than stored hostname
-l, --login print system login processes
--lookup attempt to canonicalize hostnames via DNS
-m only hostname and user associated with stdin
-p, --process print active processes spawned by init
-q, --count all login names and number of users logged on
-r, --runlevel print current runlevel
-s, --short print only name, line, and time (default)
-t, --time print last system clock change
-T, -w, --mesg add user's message status as +, - or ?
-u, --users list users logged in
--message same as -T
--writable same as -T
--help display this help and exit
--version output version information and exit
If FILE is not specified, use /var/run/utmp. /var/log/wtmp as FILE is common.
If ARG1 ARG2 given, -m presumed: 'am i' or 'mom likes' are usual.
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