centos 7 里如何判断IP是否合法
ip=123.23.2.32; [[ $ip =~ ^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$ ]] && echo legal ip || echo no leagl ip
ip=123.23.2.32; [[ $ip =~ ^(([1-9]?[0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5]).){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$ ]] && echo legal ip || echo no leagl ip