The who command of one linux Command per day displays the user information currently logged on to the system. Who -- help can be used to view command parameters. Who Command Format: who [OPTION]... [FILE | ARG1 ARG2] If FILE is not specified, the default value is/var/run/utmp www.2cto.com OPTION:-: -B-d -- login-p-r-t-T-u-B last system boot time. -D: displays dead processes, including their time. -H: displays the title of each column. -I is not recommended. It is replaced by-u. -L is not recommended. You can use -- lookup to convert hostnames through DNS. -M is the same as who am I. -P: displays the active process caused by initialization. -Q: the logon username and number of logon users are displayed. -R: displays the current running level. -S this parameter will be ignored and will not be processed. It is only responsible for solving compatibility issues with other versions of the who command. -T shows the last system clock change. -T or-w shows the user information status. -U: List login users. Author: CrazyNemo