分享一个shell脚本的坑：grep匹配+wc取值 在脚本执行后的结果与

[[email?protected] tmp]# ps -ef|grep main
root     23448 23422  0 11:40 pts/0    00:00:00 grep --color=auto main

[[email?protected] tmp]# ps -ef|grep main|grep -v grep|wc -l
0

[[email?protected] 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

[[email?protected] 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!

[[email?protected] tmp]# sh /tmp/main_check.sh
Don‘t worry! main is running!

[[email?protected] 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

[[email?protected] 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!

[[email?protected] tmp]# sh /tmp/main_check.sh
Oh!My God! It‘s broken! main is stoped!

[[email?protected] ~]# 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

[[email?protected] ~]# 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 $i:/usr/bin/ > /dev/null 2>&1
ssh -p22 [email?protected]$i "echo $i;sh /usr/bin/main_check"
done