Toolbox Aid

August 9th, 2024 1:17 PM Mr. Q Categories: Command

Command: who

The who command shows a list of users currently logged into the system. It provides information about the username, terminal, login time, and sometimes the originating IP address or hostname.

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Sample Commands and Outputs:

• who: Displays a list of users currently logged in. Sample Command and Output:

  $ who
  user1   tty1         2024-08-09 09:00
  user2   pts/0        2024-08-09 09:15 (:0)

Description:

• user1: Username of the logged-in user.
• tty1: Terminal on which the user is logged in.
• 2024-08-09 09:00: The date and time when the user logged in.
• who -a: Shows all available information including system boot time, run level changes, and user logins. Sample Command and Output:

  $ who -a
  system boot  2024-08-09 08:00
  run-level 3  2024-08-09 08:00
  user1   tty1         2024-08-09 09:00
  user2   pts/0        2024-08-09 09:15 (:0)

Description:

• -a: Includes additional information such as system boot time and run level changes.
• who -b: Displays the time of the last system boot. Sample Command and Output:

  $ who -b
  system boot  2024-08-09 08:00

Description:

• -b: Shows the date and time of the last system boot.
• who -H: Displays a header row with column names. Sample Command and Output:

  $ who -H
  NAME     LINE         TIME              COMMENT
  user1    tty1         2024-08-09 09:00
  user2    pts/0        2024-08-09 09:15 (:0)

Description:

• -H: Includes a header row in the output.

Note: The who command is useful for monitoring active users on the system and can help in managing user sessions and system activity.