How to use KILL command skillfully in Linux system, pure Dry goods!!!

1. Command format:

kill[参数][进程号]

2. Command function:

Sends the specified signal to the corresponding process. Not specifying a model will send Sigterm (15) to terminate the specified process. Such as

Can not terminate the program can be used "-kill" parameter, which sends the signal is Sigkill (9), will be strong

Process, use the PS command or the jobs command to view the process number. The root user will affect the user's

Processes, non-root users can only affect their own processes.

3. Command parameters:

-l  信号，若果不加信号的编号参数，则使用“-l”参数会列出全部的信号名称-a  当处理当前进程时，不限制命令名和进程号的对应关系-p  指定kill 命令只打印相关进程的进程号，而不发送任何信号-s  指定发送信号-u  

Attention:

1. Kill command can be with signal number option or without. If there is no signal number, the KILL command

A terminating signal (15) is emitted, which can be captured by the process, allowing the process to clean up before exiting

and release resources. You can also use kill to send a specific signal to the process. For example:

Kill-2 123

The effect is equivalent to pressing the CTRL + C key while the foreground is running the PID 123 process. However, ordinary users only

Can use the KILL command without the signal parameter or use a maximum of-9 signal.

2. Kill can have a process ID number as a parameter. When you send a signal to these processes with kill, it must be the

The master of some processes. If you attempt to revoke a process that does not have permission to revoke or revoke a process that does not exist

, you get an error message.

3, you can signal to multiple processes or terminate them.

4. When kill successfully sends a signal, the shell displays the process termination information on the screen. Sometimes

This message does not appear immediately, only if you press the ENTER key to make the Shell's command prompt reappear.

will show up.

5, it should be noted that the signal to force the process to terminate, which often brings some side effects, such as data loss or terminal

Unable to revert to a normal state. Be careful when sending a signal, only use the kill signal if it is a last resort

(9) Because the process cannot capture it first. To undo all background jobs, you can enter kill 0. Because

Some commands that run in the background start multiple processes, tracking and finding the PID of all the processes to be killed

It's a lot of trouble. At this point, using kill zero terminates all processes initiated by the current shell, which is a valid

Method.

4. Use instance: Example 1: List all signal names

命令：kill -l输出：[[email protected] test]# kill -l

 1) SIGHUP       2) SIGINT       3) SIGQUIT      4) SIGILL 5) SIGTRAP      6) SIGABRT      7) SIGBUS       8) SIGFPE 9) SIGKILL     10) SIGUSR1     11) SIGSEGV     12) SIGUSR213) SIGPIPE     14) SIGALRM     15) SIGTERM     16) SIGSTKFLT17) SIGCHLD     18) SIGCONT     19) SIGSTOP     20) SIGTSTP21) SIGTTIN     22) SIGTTOU     23) SIGURG      24) SIGXCPU25) SIGXFSZ     26) SIGVTALRM   27) SIGPROF     28) SIGWINCH29) SIGIO       30) SIGPWR      31) SIGSYS      34) SIGRTMIN35) SIGRTMIN+1  36) SIGRTMIN+2  37) SIGRTMIN+3  38) SIGRTMIN+439) SIGRTMIN+5  40) SIGRTMIN+6  41) SIGRTMIN+7  42) SIGRTMIN+843) SIGRTMIN+9  44) SIGRTMIN+10 45) SIGRTMIN+11 46) SIGRTMIN+1247) SIGRTMIN+13 48) SIGRTMIN+14 49) SIGRTMIN+15 50) SIGRTMAX-1451) SIGRTMAX-13 52) SIGRTMAX-12 53) SIGRTMAX-11 54) SIGRTMAX-1055) SIGRTMAX-9  56) SIGRTMAX-8  57) SIGRTMAX-7  58) SIGRTMAX-659) SIGRTMAX-5  60) SIGRTMAX-4  61) SIGRTMAX-3  62) SIGRTMAX-263) SIGRTMAX-1  64) SIGRTMAX

Description

Only the 9th signal (SIGKILL) can terminate the process unconditionally, other signal processes have the right to ignore.

下面是常用的信号：HUP    1    终端断线INT     2    中断（同 Ctrl + C）QUIT    3    退出（同 Ctrl + \）TERM   15    终止KILL    9    强制终止CONT   18    继续（与STOP相反， fg/bg命令）STOP    19    暂停（同 Ctrl + Z）

Example 2: Get the value of the specified signal

命令：kill -1输出：[[email protected] test]# kill -l KILL9[[email protected] test]# kill -l SIGKILL9[[email protected] test]# kill -l TERM15[[email protected] test]# kill -l SIGTERM

Example 3: First use PS to find the process, then kill with Kill

命令：kill 3268输出：[[email protected] test]# ps -ef|grep vim root      3268  2884  0 16:21 pts/1    00:00:00 vim install.logroot      3370  2822  0 16:21 pts/0    00:00:00 grep vim[[email protected] test]# kill 3268 [[email protected] test]# kill 3268 -bash: kill: (3268) - 没有那个进程

Example 4: Kill the process completely

命令：kill –9 3268 输出：[[email protected] test]# ps -ef|grep vim root      3268  2884  0 16:21 pts/1    00:00:00 vim install.logroot      3370  2822  0 16:21 pts/0    00:00:00 grep vim[[email protected] test]# kill –9 3268 [[email protected] test]# kill 3268 -bash: kill: (3268) - 没有那个进程

Example 5: Kill all processes for a specified user

命令：kill -9 $(ps -ef | grep peidalinux)kill -u peidalinux输出：[[email protected] test]# kill -9 $(ps -ef | grep peidalinux) [[email protected] test]# kill -u peidalinux

Method:
Filter out Hnlinux user processes and kill

Instance 6:init process is not to be killed

命令：kill -9 1输出：[[email protected] ~]# ps -ef|grep initroot         1     0  0 Nov02 ?        00:00:00 init [3]            root     17563 17534  0 17:37 pts/1    00:00:00 grep init[[email protected] ~]# kill -9 1[[email protected] ~]# kill -HUP 1[[email protected] ~]# ps -ef|grep initroot         1     0  0 Nov02 ?        00:00:00 init [3]            root     17565 17534  0 17:38 pts/1    00:00:00 grep init[[email protected] ~]# kill -KILL 1[[email protected] ~]# ps -ef|grep initroot         1     0  0 Nov02 ?        00:00:00 init [3]            root     17567 17534  0 17:38 pts/1    00:00:00 grep init

Description

Init is one of the most indispensable programs in Linux system operation. The so-called Init process, it is an internal

A kernel-initiated user-level process. The kernel is self-booting (it has been loaded into memory, started running, and has been initialized

All device drivers and data structures, etc.), by starting a user-level program init

To complete the boot process. As a result, Init is always the first process (its process number is always 1). Other

All processes are child processes of the INIT process, and the INIT process is not to be killed!!!

How to skillfully use KILL command in Linux system, pure Dry goods!!!