centos 7 裏如何判斷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