向你們分享一個shell腳本的坑

打算在跳板機上寫一個shell腳本，批量檢查遠程服務器上的main進程是否在健康運行中。

先找出其中一臺遠程機器，查看main進程運行狀況

[root@two002 tmp]# ps -ef|grep main
root     23448 23422  0 11:40 pts/0    00:00:00 grep --color=auto main
 
[root@two002 tmp]# ps -ef|grep main|grep -v grep|wc -l
0

shell檢查腳本以下

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

執行腳本

[root@two002 tmp]# sh -x /tmp/main_check.sh
++ grep main
++ grep -v grep
++ wc -l
++ ps -ef
+ NUM=2
+ '[' 2 -eq 0 ']'
+ echo 'Don'\''t worry! main is running!'
Don't worry! main is running!
 
[root@two002 tmp]# sh /tmp/main_check.sh
Don't worry! main is running!

如上執行結果，發現腳本執行過程當中，看到賦予NUM參數的結果值是2！可是手動執行ps -ef|grep main|grep -v grep|wc -l的結果明明是0！！
這是因爲grep匹配的問題，須要grep進行精準匹配，即"grep -w"。這就須要將main_check.sh腳本內容修改以下：

[root@two002 tmp]# cat /tmp/main_check.sh
#!/bin/bash
NUM=$(ps -ef|grep -w main|grep -v grep|wc -l)
if [ $NUM -eq 0 ];then
   echo "Oh!My God! It's broken! main is stoped!"
else
   echo "Don't worry! main is running!"
fi

再次執行檢查腳本，就OK了

[root@two002 tmp]# sh -x /tmp/main_check.sh
++ grep -w main
++ grep -v grep
++ wc -l
++ ps -ef
+ NUM=0
+ '[' 0 -eq 0 ']'
+ echo 'Oh!My God! It'\''s broken! main is stoped!'
Oh!My God! It's broken! main is stoped!
 
[root@two002 tmp]# sh /tmp/main_check.sh
Oh!My God! It's broken! main is stoped!

故在跳板機上，批量檢查遠程服務器的main進程運行狀態的腳本爲：

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

原文來自： https://www.linuxprobe.com/shel-grep-linux.html