Shell scripts are mutually exclusive settings

　　Reference: https: //blog.csdn.net/hanjiezz/article/details/79571703

　　To prevent the shell script to perform the same script at the same time need to set the mutex

　　Simple method, script execution to start generating a lock file, if the lock file exists on behalf of someone executed, the script exits

　　test.sh

#!/bin/bash
LOCKFILE="/tmp/test_lock"
if [ -f ${LOCKFILE} ]
  then
    echo "someon do the same thing"
    exit
  else
    touch ${LOCKFILE}
fi
sleep 90
if [ -f ${LOCKFILE} ]
  then
    rm -rf ${LOCKFILE}
fi

 　　sleep simulation script to perform other operations

　　Open a terminal execute the script, then the script is not finished at the time of the execution will open another terminal prompt, and then exit

 

　　If an accident or force quit the script does not execute the last step to remove lock file during execution, following a script written to avoid this problem

#!/bin/bash
if [ -f /var/run/${BASH_SOURCE[0]}.pid ]
  then
    ps -ef|grep -v grep|grep ${BASH_SOURCE[0]}|grep `cat /var/run/${BASH_SOURCE[0]}.pid` >> /dev/null
      if [ $? -eq 0 ];then
        echo "someone do the same thing"
        exit 1
      fi
fi
echo $$ > /var/run/${BASH_SOURCE[0]}.pid
sleep 90

 　　PS: $ {BASH_SOURCE [0]} is to get the current script name

　　　　Judging process for the

　　　　1, to determine whether there is a script pid

　　　　2, if the script pid, check currently running the script, if you are running and the pid pid file is run on behalf of someone else is in the running to change the script exits

              3. If you do not run a pid pid file script represents no one to run the script, put the pid pid file is written to run

     PS: script error

test.sh: 2: test.sh: Bad substitution

 　　Need to run with bash