blocks|key|243154|text|如果命令具有非零退出代码，则system返回false；如果没有命令，则返回nil。|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|243155|因此|243156|system(+"foo"+)+or+exit|code-block|syntax|javascript|243157|或|243158|system(+"foo"+)+or+raise+"Something+went+wrong+with+foo"|243159|应该是有效的，并且相当简洁。|243160|entityMap^0|E|6|M|5|12|3|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@$9|V|A|W|B|C]|$9|X|A|Y|B|C]|$9|Z|A|10|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|11|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|12|8|@]|D|@]|E|$K|L]]|$1|M|3|N|5|6|7|13|8|@]|D|@]|E|$]]|$1|O|3|P|5|J|7|14|8|@]|D|@]|E|$K|L]]|$1|Q|3|R|5|6|7|15|8|@]|D|@]|E|$]]|$1|S|3|-4|5|6|7|16|8|@]|D|@]|E|$]]]|T|$]]

<code>system</code> returns <code>false</code> if the command has an non-zero exit code, or <code>nil</code> if there is no command.

Therefore

<pre><code>system( "foo" ) or exit
</code></pre>

or

<pre><code>system( "foo" ) or raise "Something went wrong with foo"
</code></pre>

should work, and are reasonably concise.

blocks|key|243178|text|您没有捕获system调用的结果，这是返回结果代码的地方：|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|243179|exit_code+=+system("ruby+test.rb")|code-block|syntax|javascript|243180|请记住，每次system调用或等效调用(包括回号方法)都会产生一个新的shell，因此不可能捕获以前shell环境的结果。在本例中，如果一切正常，则exit_code为true，否则为nil。|243181|popen3命令提供了更多低级详细信息。|243182|entityMap|0|LINK|mutability|MUTABLE|url|http://www.ruby-doc.org/stdlib-1.9.3/libdoc/open3/rdoc/Open3.html#method-c-popen3^0|5|6|0|0|6|6|22|9|2C|4|2K|3|0|0|6|0|6|0|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|@$9|11|A|12|B|C]|$9|13|A|14|B|C]|$9|15|A|16|B|C]|$9|17|A|18|B|C]]|D|@]|E|$]]|$1|M|3|N|5|6|7|19|8|@$9|1A|A|1B|B|C]]|D|@$9|1C|A|1D|1|1E]]|E|$]]|$1|O|3|-4|5|6|7|1F|8|@]|D|@]|E|$]]]|P|$Q|$5|R|S|T|E|$U|V]]]]

You're not capturing the result of your <code>system</code> call, which is where the result code is returned:

<pre><code>exit_code = system("ruby test.rb")
</code></pre>

Remember each <code>system</code> call or equivalent, which includes the backtick-method, spawns a new shell, so it's not possible to capture the result of a previous shell's environment. In this case <code>exit_code</code> is <code>true</code> if everything worked out, <code>nil</code> otherwise.

The <a href="http://www.ruby-doc.org/stdlib-1.9.3/libdoc/open3/rdoc/Open3.html#method-c-popen3" rel="noreferrer"><code>popen3</code></a> command provides more low-level detail.

blocks|key|26371|text|一种方法是使用and或&&链接它们|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|26372|system("VBoxManage+createvm+--name+test1")+and+system("ruby+test.rb")|code-block|syntax|javascript|26373|如果第一个调用失败，则不会运行第二个调用。|26374|您可以将它们包装在一个if+()中，以提供一些流控制：|26375|if+(
++system("VBoxManage+createvm+--name+test1")+&&+
++system("ruby+test.rb")
)+
++#+do+something
else
++#+do+something+with+$?
end|26376|entityMap^0|7|3|B|2|0|0|0|B|5|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@$9|T|A|U|B|C]|$9|V|A|W|B|C]]|D|@]|E|$]]|$1|F|3|G|5|H|7|X|8|@]|D|@]|E|$I|J]]|$1|K|3|L|5|6|7|Y|8|@]|D|@]|E|$]]|$1|M|3|N|5|6|7|Z|8|@$9|10|A|11|B|C]]|D|@]|E|$]]|$1|O|3|P|5|H|7|12|8|@]|D|@]|E|$I|J]]|$1|Q|3|-4|5|6|7|13|8|@]|D|@]|E|$]]]|R|$]]

One way to do this is to chain them using <code>and</code> or <code>&amp;&amp;</code>:

<pre><code>system("VBoxManage createvm --name test1") and system("ruby test.rb")
</code></pre>

The second call won't be run if the first fails.

You can wrap those in an <code>if ()</code> to give you some flow-control:

<pre><code>if (
 system("VBoxManage createvm --name test1") &amp;&amp; 
 system("ruby test.rb")
) 
 # do something
else
 # do something with $?
end
</code></pre>

blocks|key|243204|text|对我来说，我更喜欢使用来调用外壳命令并检查$？获取进程状态。$？是一个进程状态对象，可以从这个对象中获取命令的进程信息，包括:状态码、执行状态、pid等。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|243205|$的一些有用的方法？对象：|243206|+++$?.exitstatus+=>+return+error+code++++
+++$?.success?+=>+return+true+if+error+code+is+0,+otherwise+false
+++$?.pid+=>+created+process+pid|code-block|syntax|javascript|243207|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|$]]

For me, I preferred use `` to call the shell commands and check $? to get process status. The $? is a process status object, you can get the command's process information from this object, including: status code, execution status, pid, etc.

Some useful methods of the $? object:

<pre><code> $?.exitstatus =&gt; return error code 
 $?.success? =&gt; return true if error code is 0, otherwise false
 $?.pid =&gt; created process pid
</code></pre>

blocks|key|243211|text|Ruby+2.6+added+option+to+raise+exception+in+Kernel#system|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|243212|system("command",+exception:+true)|code-block|syntax|javascript|243213|entityMap|0|LINK|mutability|MUTABLE|url|https://www.bigbinary.com/blog/ruby-2-6-added-option-to-raise-exception-in-kernel-system^0|0|1L|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]]]]

<a href="https://www.bigbinary.com/blog/ruby-2-6-added-option-to-raise-exception-in-kernel-system" rel="nofollow noreferrer">Ruby 2.6 added option to raise exception in Kernel#system</a>:
<pre><code>system(&quot;command&quot;, exception: true)
</code></pre>

I have a bunch of system calls in ruby such as the following and I want to check their exit codes simultaneously so that my script exits out if that command fails.

<pre><code>system("VBoxManage createvm --name test1")
system("ruby test.rb")
</code></pre>

I want something like

<code>system("VBoxManage createvm --name test1", 0)</code> &lt;-- where the second parameter checks the exit code and confirms that that system call was successful, and if not, it'll raise an error or do something of that sort.

Is that possible at all?

I've tried something along the lines of this and that didn't work either.

<pre><code>system("ruby test.rb")
system("echo $?")
</code></pre>

or 

<pre><code>`ruby test.rb`
exit_code = `echo $?`
if exit_code != 0
 raise 'Exit code is not zero'
end
</code></pre>

ruby system command check exit code

我在ruby中有一堆系统调用，如下所示，我想同时检查它们的退出代码，以便在该命令失败时我的脚本退出。system("VBoxManage createvm --name test1")system("ruby test.rb")我想要像这样的东西system("VBoxManage createvm --name te...

问ruby系统命令检查退出代码
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