[root@ob1 scripts]# vim test_httpd.sh
1 #!/bin/bash
2 #ss -tlnup|grep :80 >/dev/null 2>&1
3 dk=$(ss -tlnup|awk -F"[ :]+" ‘/80/{print $5}‘)
4 if [ "80" = "${dk}" ];then #use string to compare,num is not have null
5 echo "httpd is running"
6 else
7 echo "restarting"
8 /etc/init.d/httpd restart >/dev/null 2>&1
9 fi
如果服务没起就重启,if [ "80" = "${dk}" ];then 在字符串比较80 -eq dk 没起是空的时候报错,写成字符串就不报错应为字符串有空,数字没值会报错
原文：http://www.cnblogs.com/gaoyuechen/p/7571426.html