First, use ps to view the process, as follows:
$ ps -ef
……
smx 1822 1 0 11:38 ? 00:00:49 gnome-terminal
smx 1823 1822 0 11:38 ? 00:00:00 gnome-pty-helper
smx 1824 1822 0 11:38 pts/0 00:00:02 bash
smx 1827 1 4 11:38 ? 00:26:28 /usr/lib/firefox-3.6.18/firefox-bin
smx 1857 1822 0 11:38 pts/1 00:00:00 bash
smx 1880 1619 0 11:38 ? 00:00:00 update-notifier
……
smx 11946 1824 0 21:41 pts/0 00:00:00 ps -ef
or:
$ ps -aux
……
smx 1822 0.1 0.8 58484 18152 ? Sl 11:38 0:49 gnome-terminal
smx 1823 0.0 0.0 1988 712 ? S 11:38 0:00 gnome-pty-helper
smx 1824 0.0 0.1 6820 3776 pts/0 Ss 11:38 0:02 bash
smx 1827 4.3 5.8 398196 119568 ? Sl 11:38 26:13 /usr/lib/firefox-3.6.18/firefox-bin
smx 1857 0.0 0.1 6688 3644 pts/1 Ss 11:38 0:00 bash
smx 1880 0.0 0.6 41536 12620 ? S 11:38 0:00 update-notifier
……
smx 11953 0.0 0.0 2716 1064 pts/0 R+ 21:42 0:00 ps -aux
At this point, if I want to kill the Firefox process, I type in the terminal:
$ kill -s 9 1827
Where -s 9 specifies that the signal passed to the process is 9, that is, to force the process to terminate as soon as possible. See the appendix for each termination signal and its function.
1827 is the PID of Firefox found by ps above.
It's simple, but there is a problem. It doesn't matter if there are fewer processes. If there are too many processes, it will be painful. Whether it is ps -ef or ps -aux, each time you need to find the process to be killed in a large series of process information. , all eyes are spent.
Advanced articles:
Improvement 1 :
Pipe the query results of ps to grep to find processes that contain a specific string. The pipe character "|" is used to separate two commands. The output of the command to the left of the pipe character is used as the input of the command to the right of the pipe character.
$ ps -ef | grep firefox
smx 1827 1 4 11:38 ? 00:27:33 /usr/lib/firefox-3.6.18/firefox-bin
smx 12029 1824 0 21:54 pts/0 00:00:00 grep --color=auto firefox
It's refreshing this time. Then there is
$kill -s 9 1827
Or too much typing?
Improvement 2 - use pgrep :
What is the first thing that comes to your mind when you see pgrep? That's right, grep! The p in pgrep indicates that the command is a grep for process queries.
$ pgrep firefox
1827
What did you see? That's right, the PID of Firefox, and then we have to type again:
$kill -s 9 1827
Improvement 3 - use pidof:
What do you think of when you see pidof? That's right pid of xx, the literal translation is the PID of xx.
$ pidof firefox-bin
1827
Compared with pgrep, pidof must give the full name of the process. And then there's the cliché:
$kill -s 9 1827
Whether you use ps and then slowly find the process PID, use grep to find the process containing the corresponding string, or use pgrep to directly find the process PID containing the corresponding string, and then manually input it to kill to kill, it is a little troublesome. Is there a more convenient way? have!
Improvement 4:
$ps -ef | grep firefox | grep -v grep | cut -c 9-15 | xargs kill -s 9
illustrate:
The output of "grep firefox" is all processes with the keyword "firefox".
"grep -v grep" removes processes with the keyword "grep" from the listed processes.
"cut -c 9-15" is to intercept the 9th to 15th characters of the input line, which is exactly the process number PID.
The xargs command in "xargs kill -s 9" is used to use the output result (PID) of the previous command as the parameter of the "kill -s 9" command, and execute the command. "kill -s 9" will forcibly kill the specified process.
Don't you want to complain about something? yes too long
Improvement 5:
Knowing the two commands pgrep and pidof, why do you have to type such a long list!
$ pgrep firefox | xargs kill -s 9
Improvement 6:
$ ps -ef | grep firefox | awk '{print $2}' | xargs kill -9
kill: No such process
There is a more depressing place, the process has been correctly found and terminated, but the process is not found after execution.
The function of awk '{print $2}' is to print (print) the contents of the second column. According to the general article, it can be known that the second column of the ps output is exactly the PID. Pass the corresponding PID of the process to kill as a parameter through xargs to kill the corresponding process.
Improvement 7 :
Do I have to call xargs every time to pass the PID to kill? the answer is negative:
$kill -s 9 `ps -aux | grep firefox | awk '{print $2}'`
Improvement 8:
That's right, the command is still a bit long, replaced by pgrep.
$kill -s 9 `pgrep firefox`
Improvement 9 - pkill:
What did you think of when you saw pkill? That's right pgrep and kill! pkill=pgrep+kill.
$pkill -９ firefox
Explanation: "-9" means that the signal sent is 9. The difference between pkill and kill is that pkill does not need "s", and the termination signal level directly follows "-". I always thought it was "-s 9" before, and it failed to kill the process every time I ran it.
Improvement 10 --killall :
killall and pkill are similar, but if the given process name is incomplete, killall will report an error. pkill or pgrep can kill a process by giving only part of the process name.
$killall -9 firefox
Appendix: Various Signals and Their Uses
[1] Signal Description Signal number on Linux x86
| SIGABRT | Process aborted | 6 |
| SIGALRM | Signal raised by alarm | 14 |
| SIGBUS | Bus error: "access to undefined portion of memory object" | 7 |
| SIGCHLD | Child process terminated, stopped (or continued*) | 17 |
| SIGCONT | Continue if stopped | 18 |
| SIGFPE | Floating point exception: "erroneous arithmetic operation" | 8 |
| SIGHUP | Hangup | 1 |
| SEAL | Illegal instruction | 4 |
| SIGINT | Interrupt | 2 |
| SIGKILL | Kill (terminate immediately) | 9 |
| SIGPIPE | Write to pipe with no one reading | 13 |
| SO MUCH | Quit and dump core | 3 |
| SIGSEGV | Segmentation violation | 11 |
| SIGSTOP | Stop executing temporarily | 19 |
| SIGTERM | Termination (request to terminate) | 15 |
| SIGTSTP | Terminal stop signal | 20 |
| SIGTTIN | Background process attempting to read from tty ("in") | 21 |
| SIGTTOU | Background process attempting to write to tty ("out") | 22 |
| SIGUSR1 | User-defined 1 | 10 |
| SIGUSR2 | User-defined 2 | 12 |
| SIGPOLL | Pollable event | 29 |
| SIGPROF | Profiling timer expired | 27 |
| SIGSYS | Bad syscall | 31 |
| SIGTRAP | Trace/breakpoint trap | 5 |
| SIGURG | Urgent data available on socket | 23 |
| SIGVTALRM | Signal raised by timer counting virtual time: "virtual timer expired" | 26 |
| SIGXCPU | CPU time limit exceeded | 24 |
| SIGXFSZ | File size limit exceeded | 25 |