linux下使用root强制注销其他用户和终端会话tty

出处：http://blog.chinaunix.net/uid-12115233-id-390539.html

需求：
假设w输出类似这样
user1   pts/0    ...................... -bash
user1    pts/1    ...................... -bash
user2    pts/2   ...................... -bash
user2    pts/3    ...................... w

有没有命令对指定的tty注销用户？又有没有命令对指定的用户注销所有tty？

总感觉用ps kill -9 太暴力了点，也不方便......

其实可以通过skill命令来实现:
# skill
Usage:   skill [signal to send] [options] process selection criteria
Example: skill -KILL -v pts/*

The default signal is TERM. Use -l or -L to list available signals.
Particularly useful signals include HUP, INT, KILL, STOP, CONT, and 0.
Alternate signals may be specified in three ways: -SIGKILL -KILL -9

General options:
-f  fast mode            This is not currently useful.
-i  interactive use      You will be asked to approve each action.
-v  verbose output       Display information about selected processes.
-w  warnings enabled     This is not currently useful.
-n  no action            This only displays the process ID.

Selection criteria can be: terminal, user, pid, command.
The options below may be used to ensure correct interpretation.
-t  The next argument is a terminal (tty or pty).
-u  The next argument is a username.
-p  The next argument is a process ID number.
-c  The next argument is a command name.
-t 这个参数可以多利用