blocks|key|1670585|text|要清理一些乱七八糟的东西，可以使用trap。它可以提供在特定信号到达时执行的内容的列表：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1670586|trap+"echo+hello"+SIGINT|code-block|syntax|javascript|1670587|但也可用于在shell退出时执行某些操作：|1670588|trap+"killall+background"+EXIT|1670589|它是一个内置的，所以help+trap会给你信息(与bash一起工作)。如果你只想终止后台作业，你可以这样做|1670590|trap+'kill+$(jobs+-p)'+EXIT|1670591|注意使用单个'，以防止外壳立即替换$()。|1670592|entityMap^0|H|4|0|0|0|0|A|9|0|0|6|1|H|3|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|Z|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|10|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|11|8|@]|D|@]|E|$I|J]]|$1|O|3|P|5|6|7|12|8|@$9|13|A|14|B|C]]|D|@]|E|$]]|$1|Q|3|R|5|H|7|15|8|@]|D|@]|E|$I|J]]|$1|S|3|T|5|6|7|16|8|@$9|17|A|18|B|C]|$9|19|A|1A|B|C]]|D|@]|E|$]]|$1|U|3|-4|5|6|7|1B|8|@]|D|@]|E|$]]]|V|$]]

To clean up some mess, <code>trap</code> can be used. It can provide a list of stuff executed when a specific signal arrives:

<pre><code>trap "echo hello" SIGINT
</code></pre>

but can also be used to execute something if the shell exits:

<pre><code>trap "killall background" EXIT
</code></pre>

It's a builtin, so <code>help trap</code> will give you information (works with bash). If you only want to kill background jobs, you can do

<pre><code>trap 'kill $(jobs -p)' EXIT
</code></pre>

Watch out to use single <code>'</code>, to prevent the shell from substituting the <code>$()</code> immediately.

blocks|key|1455810|text|更新：https://stackoverflow.com/a/53714583/302079通过添加退出状态和清理功能改进了这一点。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1455811|trap+"exit"+INT+TERM
trap+"kill+0"+EXIT|code-block|syntax|javascript|1455812|为什么要将INT和TERM转换为exit？因为两者都应该在不进入无限循环的情况下触发kill+0。|style|CODE|1455813|为什么要在EXIT上触发kill+0？因为正常的脚本退出也应该触发kill+0。|1455814|为什么是kill+0？因为嵌套的子壳也需要被杀死。这将拿下the+whole+process+tree。|1455815|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/53714583/302079|1|https://unix.stackexchange.com/a/67552/23316^0|3|17|0|0|0|5|3|9|4|16|6|0|5|4|C|6|X|6|0|4|6|T|M|1|0^^$0|@$1|2|3|4|5|6|7|10|8|@]|9|@$A|11|B|12|1|13]]|C|$]]|$1|D|3|E|5|F|7|14|8|@]|9|@]|C|$G|H]]|$1|I|3|J|5|6|7|15|8|@$A|16|B|17|K|L]|$A|18|B|19|K|L]|$A|1A|B|1B|K|L]]|9|@]|C|$]]|$1|M|3|N|5|6|7|1C|8|@$A|1D|B|1E|K|L]|$A|1F|B|1G|K|L]|$A|1H|B|1I|K|L]]|9|@]|C|$]]|$1|O|3|P|5|6|7|1J|8|@$A|1K|B|1L|K|L]]|9|@$A|1M|B|1N|1|1O]]|C|$]]|$1|Q|3|-4|5|6|7|1P|8|@]|9|@]|C|$]]]|R|$S|$5|T|U|V|C|$W|X]]|Y|$5|T|U|V|C|$W|Z]]]]

Update: <a href="https://stackoverflow.com/a/53714583/302079">https://stackoverflow.com/a/53714583/302079</a> improves this by adding exit status and a cleanup function.

<pre><code>trap "exit" INT TERM
trap "kill 0" EXIT
</code></pre>

Why convert <code>INT</code> and <code>TERM</code> to exit? Because both should trigger the <code>kill 0</code> without entering an infinite loop. 

Why trigger <code>kill 0</code> on <code>EXIT</code>? Because normal script exits should trigger <code>kill 0</code>, too. 

Why <code>kill 0</code>? Because nested subshells need to be killed as well. This will take down <a href="https://unix.stackexchange.com/a/67552/23316">the whole process tree</a>.

blocks|key|1670862|text|一个在Linux，BSD和MacOS+X下工作的很好的版本。首先尝试发送send，如果没有成功，在10秒后终止进程。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1670863|KillJobs()+{
++++for+job+in+$(jobs+-p);+do
++++++++++++kill+-s+SIGTERM+$job+>+/dev/null+2>&1+%7C%7C+(sleep+10+&&+kill+-9+$job+>+/dev/null+2>&1+&)

++++done
}

TrapQuit()+{
++++#+Whatever+you+need+to+clean+here
++++KillJobs
}

trap+TrapQuit+EXIT|code-block|syntax|javascript|1670864|请注意，作业不包括子进程。|1670865|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|L|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|M|8|@]|9|@]|A|$]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

A nice version that works under Linux, BSD and MacOS X. First tries to send SIGTERM, and if it doesn't succeed, kills the process after 10 seconds.

<pre><code>KillJobs() {
 for job in $(jobs -p); do
 kill -s SIGTERM $job &gt; /dev/null 2&gt;&amp;1 || (sleep 10 &amp;&amp; kill -9 $job &gt; /dev/null 2&gt;&amp;1 &amp;)

 done
}

TrapQuit() {
 # Whatever you need to clean here
 KillJobs
}

trap TrapQuit EXIT
</code></pre>

Please note that jobs does not include grand children processes.

blocks|key|1455950|text|function+cleanup_func+{
++++sleep+0.5
++++echo+cleanup
}

trap+"exit+\$exit_code"+INT+TERM
trap+"exit_code=\$?;+cleanup_func;+kill+0"+EXIT

#+exit+1
#+exit+0|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1455951|与https://stackoverflow.com/a/22644006/10082476类似，但增加了退出代码|unstyled|offset|length|1455952|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/22644006/10082476^0|0|1|19|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|R|8|@]|9|@$G|S|H|T|1|U]]|A|$]]|$1|I|3|-4|5|F|7|V|8|@]|9|@]|A|$]]]|J|$K|$5|L|M|N|A|$O|P]]]]

<pre><code>function cleanup_func {
 sleep 0.5
 echo cleanup
}

trap "exit \$exit_code" INT TERM
trap "exit_code=\$?; cleanup_func; kill 0" EXIT

# exit 1
# exit 0
</code></pre>

Like <a href="https://stackoverflow.com/a/22644006/10082476">https://stackoverflow.com/a/22644006/10082476</a>, but with added exit-code

blocks|key|1455744|text|如果在子shell中调用jobs+-p，则可能无法在所有shell中运行，除非将其输出重定向到文件而不是管道中。(我假设它最初仅用于交互用途。)|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1455745|下面是什么呢？|1455746|trap+'while+kill+%25%25+2>/dev/null;+do+jobs+>+/dev/null;+done'+INT+TERM+EXIT+[...]|code-block|syntax|javascript|1455747|Debian的dash+shell需要调用“job”，如果当前作业("%25%25")丢失，它将无法更新。|1455748|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|N|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|O|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|P|8|@]|9|@]|A|$]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

jobs -p does not work in all shells if called in a sub-shell, possibly unless its output is redirected into a file but not a pipe. (I assume it was originally intended for interactive use only.)

What about the following:

<pre><code>trap 'while kill %% 2&gt;/dev/null; do jobs &gt; /dev/null; done' INT TERM EXIT [...]
</code></pre>

The call to "jobs" is needed with Debian's dash shell, which fails to update the current job ("%%") if it is missing.

blocks|key|1455865|text|我根据@tokland的答案结合来自http://veithen.github.io/2014/11/16/sigterm-propagation.html的知识进行了修改，当我注意到如果我在运行前台进程(而不是&的背景)时，trap不会触发：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1455866|#!/bin/bash

#+killable-shell.sh:+Kills+itself+and+all+children+(the+whole+process+group)+when+killed.
#+Adapted+from+http://stackoverflow.com/a/2173421+and+http://veithen.github.io/2014/11/16/sigterm-propagation.html
#+Note:+Does+not+work+(and+cannot+work)+when+the+shell+itself+is+killed+with+SIGKILL,+for+then+the+trap+is+not+triggered.
trap+"trap+-+SIGTERM+&&+echo+'Caught+SIGTERM,+sending+SIGTERM+to+process+group'+&&+kill+--+-$$"+SIGINT+SIGTERM+EXIT

echo+$@
"$@"+&
PID=$!
wait+$PID
trap+-+SIGINT+SIGTERM+EXIT
wait+$PID|code-block|syntax|javascript|1455867|它工作的示例：|1455868|$+bash+killable-shell.sh+sleep+100
sleep+100
%5EZ
[1]++%2B+31568+suspended++bash+killable-shell.sh+sleep+100

$+ps+aux+%7C+grep+"sleep"
niklas+++31568++0.0++0.0++19640++1440+pts/18+++T++++01:30+++0:00+bash+killable-shell.sh+sleep+100
niklas+++31569++0.0++0.0++14404+++616+pts/18+++T++++01:30+++0:00+sleep+100
niklas+++31605++0.0++0.0++18956+++936+pts/18+++S%2B+++01:30+++0:00+grep+--color=auto+sleep

$+bg
[1]++%2B+31568+continued++bash+killable-shell.sh+sleep+100

$+kill+31568
Caught+SIGTERM,+sending+SIGTERM+to+process+group
[1]++%2B+31568+terminated++bash+killable-shell.sh+sleep+100

$+ps+aux+%7C+grep+"sleep"
niklas+++31717++0.0++0.0++18956+++936+pts/18+++S%2B+++01:31+++0:00+grep+--color=auto+sleep|1455869|entityMap|0|LINK|mutability|MUTABLE|url|http://veithen.github.io/2014/11/16/sigterm-propagation.html^0|2Y|1|35|4|I|1O|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@$9|11|A|12|1|13]]|E|$]]|$1|F|3|G|5|H|7|14|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|15|8|@]|D|@]|E|$]]|$1|M|3|N|5|H|7|16|8|@]|D|@]|E|$I|J]]|$1|O|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

I made an adaption of @tokland's answer combined with the knowledge from <a href="http://veithen.github.io/2014/11/16/sigterm-propagation.html" rel="nofollow">http://veithen.github.io/2014/11/16/sigterm-propagation.html</a> when I noticed that <code>trap</code> doesn't trigger if I'm running a foreground process (not backgrounded with <code>&amp;</code>):

<pre><code>#!/bin/bash

# killable-shell.sh: Kills itself and all children (the whole process group) when killed.
# Adapted from http://stackoverflow.com/a/2173421 and http://veithen.github.io/2014/11/16/sigterm-propagation.html
# Note: Does not work (and cannot work) when the shell itself is killed with SIGKILL, for then the trap is not triggered.
trap "trap - SIGTERM &amp;&amp; echo 'Caught SIGTERM, sending SIGTERM to process group' &amp;&amp; kill -- -$$" SIGINT SIGTERM EXIT

echo $@
"$@" &amp;
PID=$!
wait $PID
trap - SIGINT SIGTERM EXIT
wait $PID
</code></pre>

Example of it working:

<pre><code>$ bash killable-shell.sh sleep 100
sleep 100
^Z
[1] + 31568 suspended bash killable-shell.sh sleep 100

$ ps aux | grep "sleep"
niklas 31568 0.0 0.0 19640 1440 pts/18 T 01:30 0:00 bash killable-shell.sh sleep 100
niklas 31569 0.0 0.0 14404 616 pts/18 T 01:30 0:00 sleep 100
niklas 31605 0.0 0.0 18956 936 pts/18 S+ 01:30 0:00 grep --color=auto sleep

$ bg
[1] + 31568 continued bash killable-shell.sh sleep 100

$ kill 31568
Caught SIGTERM, sending SIGTERM to process group
[1] + 31568 terminated bash killable-shell.sh sleep 100

$ ps aux | grep "sleep"
niklas 31717 0.0 0.0 18956 936 pts/18 S+ 01:31 0:00 grep --color=auto sleep
</code></pre>

blocks|key|1456017|text|为了多样性，我将发布https://stackoverflow.com/a/2173421/102484的变体，因为该解决方案会在我的环境中导致消息“已终止”：|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|1456018|trap+'test+-z+"$intrap"+&&+export+intrap=1+&&+kill+--+-$$'+SIGINT+SIGTERM+EXIT|code-block|syntax|javascript|1456019|entityMap|0|LINK|mutability|MUTABLE|url|https://stackoverflow.com/a/2173421/102484^0|A|16|0|0|0^^$0|@$1|2|3|4|5|6|7|Q|8|@]|9|@$A|R|B|S|1|T]]|C|$]]|$1|D|3|E|5|F|7|U|8|@]|9|@]|C|$G|H]]|$1|I|3|-4|5|6|7|V|8|@]|9|@]|C|$]]]|J|$K|$5|L|M|N|C|$O|P]]]]

Just for diversity I will post variation of <a href="https://stackoverflow.com/a/2173421/102484">https://stackoverflow.com/a/2173421/102484</a> , because that solution leads to message "Terminated" in my environment:

<pre><code>trap 'test -z "$intrap" &amp;&amp; export intrap=1 &amp;&amp; kill -- -$$' SIGINT SIGTERM EXIT
</code></pre>

blocks|key|1455549|text|因此，在脚本加载过程中编写脚本。运行一个killall+(或您的操作系统上可用的任何东西)命令，该命令在脚本完成后立即执行。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1455550|entityMap^0|K|7|0^^$0|@$1|2|3|4|5|6|7|H|8|@$9|I|A|J|B|C]]|D|@]|E|$]]|$1|F|3|-4|5|6|7|K|8|@]|D|@]|E|$]]]|G|$]]

So script the loading of the script. Run a <code>killall</code> (or whatever is available on your OS) command that executes as soon as the script is finished.

blocks|key|1455670|text|另一种选择是将脚本自身设置为进程组领导者，并在退出时捕获进程组上的killpg。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1455671|entityMap^0|0^^$0|@$1|2|3|4|5|6|7|D|8|@]|9|@]|A|$]]|$1|B|3|-4|5|6|7|E|8|@]|9|@]|A|$]]]|C|$]]

Another option is it to have the script set itself as the process group leader, and trap a killpg on your process group on exit.

I am looking for a way to clean up the mess when my top-level script exits.

Especially if I want to use <code>set -e</code>, I wish the background process would die when the script exits.

How do I kill background processes / jobs when my shell script exits?

Debian

Linux

MacOS

我正在寻找一种方法来清理我的顶级脚本退出时的混乱。尤其是如果我想使用set -e，我希望后台进程在脚本退出时会死掉。

问如何在shell脚本退出时终止后台进程/作业？
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