linux bash获取后台进程的id

在 bash 中，下面两个变量有特殊含义

• $$ is the current script's pid
• $! is the pid of the last background process

#!/bin/bash

./other.sh > /dev/null 2>&1 &
proc_pid=$!
# wait process to be killed
wait $proc_pid > /dev/null 2>&1