Linux 查看登录用户信息 who & whoami

在一台服务器上，同一时间往往会有很难多人同时登录。

who 命令可以查看当前系统中有哪些人登录，以及他们都工作在哪个控制台上。

这样可以很方便的监控机器的登录人信息，并对系统操作进行安全监控。

[root@node1 /]# who
root     pts/0        2019-11-21 23:10 (XX..)
root     pts/2        2019-11-18 11:39 (XX..)

效果如下：

有时候，可能会忘记自己是以什么身份登录到系统，尤其是需要以特定身份启动或者停止某个服务器程序时。

这时候，可以使用 whoami 命令。（即为“我是谁”的英文意思组合）

[root@node1 /]# whoami
root

效果如下：

额外补充

who 命令的手册说明如下（可以使用 man who 命令查看使用手册）：

WHO(1)                                                                                 User Commands                                                                                WHO(1)

NAME
       who - show who is logged on

SYNOPSIS
       who [OPTION]... [ FILE | ARG1 ARG2 ]

DESCRIPTION
       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

       -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.

       GNU coreutils online help: <http://www.gnu.org/software/coreutils/> Report who translation bugs to <http://translationproject.org/team/>

AUTHOR
       Written by Joseph Arceneaux, David MacKenzie, and Michael Stone.

COPYRIGHT
       Copyright © 2013 Free Software Foundation, Inc.  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>.
       This is free software: you are free to change and redistribute it.  There is NO WARRANTY, to the extent permitted by law.

SEE ALSO
       The full documentation for who is maintained as a Texinfo manual.  If the info and who programs are properly installed at your site, the command

              info coreutils 'who invocation'

       should give you access to the complete manual.