shell脚本的坑：grep匹配+wc取值在脚本执行后的结果与手动执行结果不一致

ゝ一世哀愁。 2023-06-27 06:23 33阅读 0赞

打算在跳板机上写一个shell脚本，批量检查远程服务器上的main进程是否在健康运行中。

**先找出其中一台远程机器，查看main进程运行情况**

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 <td> <code>[root@two002 tmp]</code><code># ps -ef|grep main</code> <code>root&nbsp;&nbsp;&nbsp;&nbsp; 23448 23422&nbsp; 0 11:40 pts</code><code>/0</code>&nbsp;&nbsp;&nbsp;&nbsp;<code>00:00:00&nbsp;</code><code>grep</code>&nbsp;<code>--color=auto main</code> &nbsp; <code>[root@two002 tmp]</code><code># ps -ef|grep main|grep -v grep|wc -l</code> <code>0</code> </td> 
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**shell检查脚本如下**

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 <td> <code>[root@two002 tmp]</code><code># cat /tmp/main_check.sh</code> <code>#!/bin/bash</code> <code>NUM=$(</code><code>ps</code>&nbsp;<code>-ef|</code><code>grep</code>&nbsp;<code>main|</code><code>grep</code>&nbsp;<code>-</code><code>v</code>&nbsp;<code>grep</code><code>|</code><code>wc</code>&nbsp;<code>-l)</code> <code>if</code>&nbsp;<code>[ $NUM -</code><code>eq</code>&nbsp;<code>0 ];</code><code>then</code> <code>&nbsp;&nbsp;&nbsp;</code><code>echo</code>&nbsp;<code>"It's not good! main is stoped!"</code> <code>else</code> <code>&nbsp;&nbsp;&nbsp;</code><code>echo</code>&nbsp;<code>"Don't worry! main is running!"</code> <code>fi</code> </td> 
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**执行脚本**

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 <td> <code>[root@two002 tmp]</code><code># sh -x /tmp/main_check.sh</code> <code>++&nbsp;</code><code>grep</code>&nbsp;<code>main</code> <code>++&nbsp;</code><code>grep</code>&nbsp;<code>-</code><code>v</code>&nbsp;<code>grep</code> <code>++&nbsp;</code><code>wc</code>&nbsp;<code>-l</code> <code>++&nbsp;</code><code>ps</code>&nbsp;<code>-ef</code> <code>+ NUM=2</code> <code>+&nbsp;</code><code>'['</code>&nbsp;<code>2 -</code><code>eq</code>&nbsp;<code>0&nbsp;</code><code>']'</code> <code>+&nbsp;</code><code>echo</code>&nbsp;<code>'Don'</code><code>\</code><code>''</code><code>t worry! main is running!'</code> <code>Don't worry! main is running!</code> &nbsp; <code>[root@two002 tmp]</code><code># sh /tmp/main_check.sh</code> <code>Don't worry! main is running!</code> </td> 
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如上执行结果，**发现脚本执行过程中，看到赋予NUM参数的结果值是2！但是手动执行ps -ef|grep main|grep -v grep|wc -l的结果明明是0！！**  
这是由于grep匹配的问题，需要grep进行精准匹配，即"grep -w"。这就**需要将main\_check.sh脚本内容修改如下**：

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 <td> <code>[root@two002 tmp]</code><code># cat /tmp/main_check.sh</code> <code>#!/bin/bash</code> <code>NUM=$(</code><code>ps</code>&nbsp;<code>-ef|</code><code>grep</code>&nbsp;<code>-w main|</code><code>grep</code>&nbsp;<code>-</code><code>v</code>&nbsp;<code>grep</code><code>|</code><code>wc</code>&nbsp;<code>-l)</code> <code>if</code>&nbsp;<code>[ $NUM -</code><code>eq</code>&nbsp;<code>0 ];</code><code>then</code> <code>&nbsp;&nbsp;&nbsp;</code><code>echo</code>&nbsp;<code>"Oh!My God! It's broken! main is stoped!"</code> <code>else</code> <code>&nbsp;&nbsp;&nbsp;</code><code>echo</code>&nbsp;<code>"Don't worry! main is running!"</code> <code>fi</code> </td> 
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**再次执行检查脚本，就OK了**

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 <td> <code>[root@two002 tmp]</code><code># sh -x /tmp/main_check.sh</code> <code>++&nbsp;</code><code>grep</code>&nbsp;<code>-w main</code> <code>++&nbsp;</code><code>grep</code>&nbsp;<code>-</code><code>v</code>&nbsp;<code>grep</code> <code>++&nbsp;</code><code>wc</code>&nbsp;<code>-l</code> <code>++&nbsp;</code><code>ps</code>&nbsp;<code>-ef</code> <code>+ NUM=0</code> <code>+&nbsp;</code><code>'['</code>&nbsp;<code>0 -</code><code>eq</code>&nbsp;<code>0&nbsp;</code><code>']'</code> <code>+&nbsp;</code><code>echo</code>&nbsp;<code>'Oh!My God! It'</code><code>\</code><code>''</code><code>s broken! main is stoped!'</code> <code>Oh!My God! It's broken! main is stoped!</code> &nbsp; <code>[root@two002 tmp]</code><code># sh /tmp/main_check.sh</code> <code>Oh!My God! It's broken! main is stoped!</code> </td> 
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**故在跳板机上，批量检查远程服务器的main进程运行状态的脚本为：**

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 <td> <code>[root@tiaoban ~]</code><code># cat /usr/bin/main_check</code> <code>#!/bin/bash</code> <code>NUM=$(</code><code>ps</code>&nbsp;<code>-ef|</code><code>grep</code>&nbsp;<code>-w main|</code><code>grep</code>&nbsp;<code>-</code><code>v</code>&nbsp;<code>grep</code><code>|</code><code>wc</code>&nbsp;<code>-l)</code> <code>if</code>&nbsp;<code>[ $NUM -</code><code>eq</code>&nbsp;<code>0 ];</code><code>then</code> <code>&nbsp;&nbsp;&nbsp;</code><code>echo</code>&nbsp;<code>"Oh!My God! It's broken! main is stoped!"</code> <code>else</code> <code>&nbsp;&nbsp;&nbsp;</code><code>echo</code>&nbsp;<code>"Don't worry! main is running!"</code> <code>fi</code> &nbsp; <code>[root@tiaoban ~]</code><code># cat /opt/script/main_check.sh</code> <code>#!/bin/bash</code> &nbsp; <code>for</code>&nbsp;<code>i&nbsp;</code><code>in</code>&nbsp;<code>$(</code><code>cat</code>&nbsp;<code>/opt/ip</code><code>.list)</code> <code>do</code> <code>/usr/bin/rsync</code>&nbsp;<code>-e&nbsp;</code><code>"ssh -p22"</code>&nbsp;<code>-avpgolr&nbsp;</code><code>/usr/bin/main_check</code>&nbsp;<code>$i:</code><code>/usr/bin/</code>&nbsp;<code>&gt;&nbsp;</code><code>/dev/null</code>&nbsp;<code>2&gt;&amp;1</code> <code>ssh</code>&nbsp;<code>-p22 root@$i&nbsp;</code><code>"echo $i;sh /usr/bin/main_check"</code> <code>done</code><code>　　</code> </td> 
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