Linux pkill command

作用

pkill 用做管理进程时，pkill 命令和 killall 命令的用法相同，都是通过进程名杀死一类进程
pkill 另一重要的功能就是按照终端用户来剔出用户登录

用法

1. 语法格式

   pkill [options] pattern

2. 参数选项

   -<sig>, --signal <sig>    signal to send (either number or name)
   -e, --echo                display what is killed
   -c, --count               count of matching processes
   -f, --full                use full process name to match
   -g, --pgroup <PGID,...>   match listed process group IDs
   -G, --group <GID,...>     match real group IDs
   -n, --newest              select most recently started
   -o, --oldest              select least recently started
   -P, --parent <PPID,...>   match only child processes of the given parent
   -s, --session <SID,...>   match session IDs
   -t, --terminal <tty,...>  match by controlling terminal
   -u, --euid <ID,...>       match by effective IDs
   -U, --uid <ID,...>        match by real IDs
   -x, --exact               match exactly with the command name
   -F, --pidfile <file>      read PIDs from file
   -L, --logpidfile          fail if PID file is not locked
   --ns <PID>                match the processes that belong to the same
                             namespace as <pid>
   --nslist <ns,...>         list which namespaces will be considered for
                             the --ns option.
                             Available namespaces: ipc, mnt, net, pid, user, uts
      
   -h, --help     display this help and exit
   -V, --version  output version information and exi

3. 用法示例

   用做进程管理，根据进程名杀死一类进程

   语法格式

   pkill [信号] 进程名

   命令常用的信号及其含义

   信号编号	信号名	含义
   0	EXIT	程序退出时收到该信息。
   1	HUP	挂掉电话线或终端连接的挂起信号，这个信号也会造成某些进程在没有终止的情况下重新初始化。
   2	INT	表示结束进程，但并不是强制性的，常用的 “Ctrl+C” 组合键发出就是一个 kill -2 的信号。
   3	QUIT	退出。
   9	KILL	杀死进程，即强制结束进程。
   11	SEGV	段错误。
   15	TERM	正常结束进程，是 kill 命令的默认信号。

   用法示例

   # 查看python进程
   [root@hadoop-centos-01 ~]# pstree -p | grep python
              |            |-sshd(33793)---bash(33803)---python(34176)
   [root@hadoop-centos-01 ~]#
   [root@hadoop-centos-01 ~]# ps -ef | grep python
   root      34176  33803  0 22:30 pts/2    00:00:00 python
   root      34188  33542  0 22:31 pts/1    00:00:00 grep --color=auto python
   
   # 执行pkill后再去查看，python进程已被杀死
   [root@hadoop-centos-01 ~]# pkill -kill python
   [root@hadoop-centos-01 ~]# pstree -p | grep python
   [root@hadoop-centos-01 ~]# ps -ef | grep python
   root      34241  33542  0 22:33 pts/1    00:00:00 grep --color=auto python

   踢出登陆用户

   语法格式

   pkill [-t 终端号] 进程名

   用法示例

   [root@hadoop-centos-01 ~]# w # 查看当前登陆的用户
    22:47:54 up 1 day, 16:20,  4 users,  load average: 0.00, 0.01, 0.05
   USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
   root     pts/0    192.168.244.6    08:03   14:43m  0.13s  0.13s -bash
   root     pts/1    192.168.244.6    21:56    2.00s  0.41s  0.01s w
   root     pts/2    192.168.244.6    22:03   18.00s  0.10s  0.10s -bash
   root     pts/3    192.168.244.6    06:35   14:43m  0.17s  0.17s -bash
   
   [root@hadoop-centos-01 ~]#
   [root@hadoop-centos-01 ~]# pkill -kill -t pts/2
   [root@hadoop-centos-01 ~]# w # 再次查看，pts/2已被杀掉
    22:51:26 up 1 day, 16:24,  3 users,  load average: 0.01, 0.02, 0.05
   USER     TTY      FROM             LOGIN@   IDLE   JCPU   PCPU WHAT
   root     pts/0    192.168.244.6    08:03   14:46m  0.13s  0.13s -bash
   root     pts/1    192.168.244.6    21:56    6.00s  0.43s  0.02s w
   root     pts/3    192.168.244.6    06:35   14:47m  0.17s  0.17s -bash