Centos lists all currently logged-on users

List all currently logged-on user commands: who is used to view current online users. This command is very useful. If you want to establish instant communication with other users, such as using the talk command, you must first make sure that the user is online. Otherwise, the talk process cannot be established. Another example is that the system administrator also needs to use the who command to monitor what every login user is doing at this moment. The common syntax format of the who command is as follows: who [imqsuwHT] [-- c lists all currently logged on user commands: who

This command is used to view the current online users. This command is very useful. If you want to establish instant communication with other users, such as using the talk command, you must first make sure that the user is online. Otherwise, the talk process cannot be established. Another example is that the system administrator also needs to use the who command to monitor what every login user is doing at this moment. The common syntax format of the who command is as follows: who [imqsuwHT] [-- count] [-- idle] [-- heading] [-- help] [-- message] [-- mesg] [-- version] [-- writable] [file] [am I] all options are optional, that is to say, the who command can be used separately. If you do not use any options, the who command displays the following three items: login name: logon username, terminal line: terminal device, and login time: the time when you log on to the system. If two optional parameters are provided, the who command only displays the user name, logon terminal, and logon time of the who program. These two parameters are usually "am I", that is, the command format is "who am I ". The following describes the common parameters of the who command. -M is the same as "who am I" and displays the user name that runs the program. -Q, -- count only displays the number of logon accounts and users. this option takes precedence over other options. -S ignore. It is mainly used for compatibility with who commands of other versions. -I,-u, -- idle shows the last time the user has performed the system operation since the logon time, that is, the "daze" time.