blocks|key|1566917|text|将此代码添加到脚本的开头：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1566918|set+-e|code-block|syntax|javascript|1566919|如果一个简单的命令以非零的退出值退出，这将导致shell立即退出。简单的命令是任何不属于if、while或until测试的命令，或者不属于&&或%7C%7C列表的命令。|1566920|有关更多详细信息，请参阅"set“内部命令上的bash(1)+man+page。|offset|length|1566921|我个人几乎所有的shell脚本都以"set+-e“开头。让脚本顽固地在中间部分失败并破坏脚本其余部分的假设时继续运行，这真的很烦人。|1566922|entityMap|0|LINK|mutability|MUTABLE|url|https://ss64.com/bash/set.html^0|0|0|0|N|G|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|Y|8|@]|9|@]|A|$]]|$1|I|3|J|5|6|7|Z|8|@]|9|@$K|10|L|11|1|12]]|A|$]]|$1|M|3|N|5|6|7|13|8|@]|9|@]|A|$]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|A|$]]]|P|$Q|$5|R|S|T|A|$U|V]]]]

Add this to the beginning of the script:

<pre><code>set -e
</code></pre>

This will cause the shell to exit immediately if a simple command exits with a nonzero exit value. A simple command is any command not part of an if, while, or until test, or part of an &amp;&amp; or || list.

See the <a href="https://ss64.com/bash/set.html" rel="noreferrer">bash(1) man page</a> on the "set" internal command for more details.

I personally start almost all shell scripts with "set -e". It's really annoying to have a script stubbornly continue when something fails in the middle and breaks assumptions for the rest of the script.

blocks|key|1566957|text|类似这样的表达式|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1566958|dosomething1+&&+dosomething2+&&+dosomething3|code-block|syntax|javascript|1566959|当其中一个命令返回非零值时，将停止处理。例如，下面的命令永远不会打印"done"：|1566960|cat+nosuchfile+&&+echo+"done"
echo+$?
1|1566961|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

An expression like

<pre><code>dosomething1 &amp;&amp; dosomething2 &amp;&amp; dosomething3
</code></pre>

will stop processing when one of the commands returns with a non-zero value. For example, the following command will never print "done":

<pre><code>cat nosuchfile &amp;&amp; echo "done"
echo $?
1
</code></pre>

blocks|key|1351517|text|在顶部运行-e或set+-e。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1351518|还可以看看set+-u。|1351519|entityMap^0|5|2|8|6|0|5|6|0^^$0|@$1|2|3|4|5|6|7|J|8|@$9|K|A|L|B|C]|$9|M|A|N|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|O|8|@$9|P|A|Q|B|C]]|D|@]|E|$]]|$1|H|3|-4|5|6|7|R|8|@]|D|@]|E|$]]]|I|$]]

Run it with <code>-e</code> or <code>set -e</code> at the top.

Also look at <code>set -u</code>.

blocks|key|1351581|text|示例中的if语句是不必要的。就像这样做：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1351582|dosomething1+%7C%7C+exit+1|code-block|syntax|javascript|1351583|如果您采纳了Ville+Laurikari的建议并使用set+-e，那么对于某些命令，您可能需要使用以下命令：|offset|length|style|CODE|1351584|dosomething+%7C%7C+true|1351585|即使命令失败，%7C%7C+true也会使命令管道具有true返回值，因此-e选项不会终止脚本。|1351586|entityMap^0|0|0|R|6|0|0|7|7|N|4|X|2|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|D|7|X|8|@]|9|@]|A|$E|F]]|$1|O|3|P|5|6|7|Y|8|@$I|Z|J|10|K|L]|$I|11|J|12|K|L]|$I|13|J|14|K|L]]|9|@]|A|$]]|$1|Q|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|R|$]]

The if statements in your example are unnecessary. Just do it like this:

<pre><code>dosomething1 || exit 1
</code></pre>

If you take Ville Laurikari's advice and use <code>set -e</code> then for some commands you may need to use this:

<pre><code>dosomething || true
</code></pre>

The <code>|| true</code> will make the command pipeline have a <code>true</code> return value even if the command fails so the the <code>-e</code> option will not kill the script.

blocks|key|1567112|text|如果你需要在退出时进行清理，你也可以使用带伪信号ERR的'trap‘。这与捕获INT或任何其他信号的方式相同；如果任何命令以非零值退出，bash都会抛出ERR：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1567113|#+Create+the+trap+with+++
#++++trap+COMMAND+SIGNAME+[SIGNAME2+SIGNAME3...]
trap+"rm+-f+/tmp/$MYTMPFILE;+exit+1"+ERR+INT+TERM
command1
command2
command3
#+Partially+turn+off+the+trap.
trap+-+ERR
#+Now+a+control-C+will+still+cause+cleanup,+but
#+a+nonzero+exit+code+won't:
ps+aux+%7C+grep+blahblahblah|code-block|syntax|javascript|1567114|或者，特别是当您使用"set+-e“时，您可以捕获退出；然后，当脚本出于任何原因退出时，您的陷阱将被执行，包括正常结束、中断、由-e选项导致的退出等。|1567115|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|$]]

If you have cleanup you need to do on exit, you can also use 'trap' with the pseudo-signal ERR. This works the same way as trapping INT or any other signal; bash throws ERR if any command exits with a nonzero value:

<pre><code># Create the trap with 
# trap COMMAND SIGNAME [SIGNAME2 SIGNAME3...]
trap "rm -f /tmp/$MYTMPFILE; exit 1" ERR INT TERM
command1
command2
command3
# Partially turn off the trap.
trap - ERR
# Now a control-C will still cause cleanup, but
# a nonzero exit code won't:
ps aux | grep blahblahblah
</code></pre>

Or, especially if you're using "set -e", you could trap EXIT; your trap will then be executed when the script exits for any reason, including a normal end, interrupts, an exit caused by the -e option, etc.

blocks|key|1351684|text|很少需要$?变量。应该始终将伪习惯用法command;+if+[+$?+-eq+0+];+then+X;+fi编写为if+command;+then+X;+fi。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1351685|需要$?的情况是需要对照多个值进行检查：|1351686|command
case+$?+in
++(0)+X;;
++(1)+Y;;
++(2)+Z;;
esac|code-block|syntax|javascript|1351687|或者当$?需要重用或以其他方式操作时：|1351688|if+command;+then
++echo+"command+successful"+>&2
else
++ret=$?
++echo+"command+failed+with+exit+code+$ret"+>&2
++exit+$ret
fi|1351689|entityMap^0|4|2|J|10|1M|M|0|2|2|0|0|3|2|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]|$9|X|A|Y|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|13|8|@$9|14|A|15|B|C]]|D|@]|E|$]]|$1|O|3|P|5|J|7|16|8|@]|D|@]|E|$K|L]]|$1|Q|3|-4|5|6|7|17|8|@]|D|@]|E|$]]]|R|$]]

The <code>$?</code> variable is rarely needed. The pseudo-idiom <code>command; if [ $? -eq 0 ]; then X; fi</code> should always be written as <code>if command; then X; fi</code>.

The cases where <code>$?</code> is required is when it needs to be checked against multiple values:

<pre><code>command
case $? in
 (0) X;;
 (1) Y;;
 (2) Z;;
esac
</code></pre>

or when <code>$?</code> needs to be reused or otherwise manipulated:

<pre><code>if command; then
 echo "command successful" &gt;&amp;2
else
 ret=$?
 echo "command failed with exit code $ret" &gt;&amp;2
 exit $ret
fi
</code></pre>

blocks|key|1567225|text|我只是抛出了另一个供参考的问题，因为Mark+Edgars的输入有一个额外的问题，下面是一个额外的例子，涉及到整个主题：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1567226|[[+`cmd`+]]+&&+echo+success_else_silence|code-block|syntax|javascript|1567227|和某人展示的cmd+%7C%7C+exit+errcode是一样的。|offset|length|style|CODE|1567228|例如，如果分区已挂载，我希望确保该分区已卸载：|1567229|[[+`mount+%7C+grep+/dev/sda1`+]]+&&+umount+/dev/sda1|1567230|entityMap^0|0|0|6|J|0|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@$I|V|J|W|K|L]]|9|@]|A|$]]|$1|M|3|N|5|6|7|X|8|@]|9|@]|A|$]]|$1|O|3|P|5|D|7|Y|8|@]|9|@]|A|$E|F]]|$1|Q|3|-4|5|6|7|Z|8|@]|9|@]|A|$]]]|R|$]]

I am just throwing in another one for reference since there was an additional question to Mark Edgars input and here is an additional example and touches on the topic overall:
<pre><code>[[ `cmd` ]] &amp;&amp; echo success_else_silence
</code></pre>
Which is the same as <code>cmd || exit errcode</code> as someone showed.
For example, I want to make sure a partition is unmounted if mounted:
<pre><code>[[ `mount | grep /dev/sda1` ]] &amp;&amp; umount /dev/sda1
</code></pre>

blocks|key|1351764|text|#!/bin/bash+-e|type|code-block|depth|inlineStyleRanges|entityRanges|data|syntax|javascript|1351765|应该足够了。|unstyled|1351766|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$B|C]]|$1|D|3|E|5|F|7|J|8|@]|9|@]|A|$]]|$1|G|3|-4|5|F|7|K|8|@]|9|@]|A|$]]]|H|$]]

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

should suffice.

blocks|key|1351807|text|出错时，下面的脚本将打印一条红色的错误消息并退出。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1351808|将这段代码放在bash脚本的顶部：|1351809|#+BASH+error+handling:
#+++exit+on+command+failure
set+-e
#+++keep+track+of+the+last+executed+command
trap+'LAST_COMMAND=$CURRENT_COMMAND;+CURRENT_COMMAND=$BASH_COMMAND'+DEBUG
#+++on+error:+print+the+failed+command
trap+'ERROR_CODE=$?;+FAILED_COMMAND=$LAST_COMMAND;+tput+setaf+1;+echo+"ERROR:+command+\"$FAILED_COMMAND\"+failed+with+exit+code+$ERROR_CODE";+put+sgr0;'+ERR+INT+TERM|code-block|syntax|javascript|1351810|entityMap^0|0|0|0^^$0|@$1|2|3|4|5|6|7|K|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|L|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|M|8|@]|9|@]|A|$G|H]]|$1|I|3|-4|5|6|7|N|8|@]|9|@]|A|$]]]|J|$]]

On error, the below script will print a RED error message and exit. 
Put this at the top of your bash script:
<pre><code># BASH error handling:
# exit on command failure
set -e
# keep track of the last executed command
trap 'LAST_COMMAND=$CURRENT_COMMAND; CURRENT_COMMAND=$BASH_COMMAND' DEBUG
# on error: print the failed command
trap 'ERROR_CODE=$?; FAILED_COMMAND=$LAST_COMMAND; tput setaf 1; echo &quot;ERROR: command \&quot;$FAILED_COMMAND\&quot; failed with exit code $ERROR_CODE&quot;; put sgr0;' ERR INT TERM
</code></pre>

I have a Bash shell script that invokes a number of commands.
I would like to have the shell script automatically exit with a return value of 1 if any of the commands return a non-zero value.
Is this possible without explicitly checking the result of each command?
For example,
<pre><code>dosomething1
if [[ $? -ne 0 ]]; then
 exit 1
fi

dosomething2
if [[ $? -ne 0 ]]; then
 exit 1
fi
</code></pre>

Aborting a shell script if any command returns a non-zero value

我有一个调用许多命令的Bash shell脚本。如果任何命令返回非零值，我希望shell脚本自动退出，返回值为1。如果不显式检查每个命令的结果，这是可能的吗？例如,dosomething1if [[ $? -ne 0 ]]; then    exit 1fidosomething2if [[ $? -ne 0 ]]; ...

问如果任何命令返回非零值，则中止shell脚本
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