注意：监控方法可以为端口、进程、、URL模拟访问方式，或者三种方法综合。
说明：由于截止到目前仅讲了if语句，因此，就请大家用if语句来实现。
考试时间:15分钟

[root@oldboy-B scripts]# cat apachemon
#!/bin/sh
#created by oldboy 20110523
#QQ 31333741
. /etc/init.d/functions
HTTPPRONUM=`ps -ef|grep http|grep -v grep|wc -l`
#if [ $HTTPPRONUM -lt 1 ];then

if [[ $HTTPPRONUM -lt 1 ]];then
action “httpd is not running” /bin/false
action “httpd is not running” /bin/false >/tmp/httpd.log
httpdctl restart >/dev/null 2>&1
action “httpd is restart” /bin/true
mail -s “`uname -n`’s httpd restarted at `(date)`” 31333741@qq.com exit 1
else
action “httpd is running” /bin/true
exit 0
fi

[root@oldboy-B scripts]# apachemon
httpd is running [确定]
[root@oldboy-B scripts]# pkill httpd
[root@oldboy-B scripts]# ps -ef|grep http|grep -v grep
[root@oldboy-B scripts]# apachemon
httpd is not running [失败]
httpd is restart [确定]
[root@oldboy-B scripts]# ps -ef|grep http|grep -v grep
root 5845 1 1 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5852 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5853 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5854 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5855 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5856 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5857 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5858 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart
apache 5859 5845 0 15:59 00:00:00 /usr/sbin/httpd -k restart

###脚本改进####
脚本改进测试：
[root@oldboy-B /]# echo oldboytest >/var/www/html/index.htm
[root@oldboy-B /]# wget –quiet –spider http://10.0.0.161/index.htm
[root@oldboy-B /]# echo $
0
[root@oldboy-B /]# ll index.htm
ls: index.htm: 没有那个文件或目录
[root@oldboy-B scripts]# cat apachemon1
#!/bin/sh
#created by oldboy 20110523
#QQ 31333741
. /etc/init.d/functions
#HTTPPRONUM=`ps -ef|grep http|grep -v grep|wc -l` #=====>这个是基于http方式进行判断
wget –quiet –spider http://10.0.0.161/index.htm #=====>这个是基于WGET URL方式进行判断
if [ $ -ne 0 ];then
action “httpd is not running” /bin/false >/tmp/httpd.log
httpdctl restart >/dev/null 2>&1
action “httpd is restart” /bin/true >>/tmp/httpd.log
mail -s “`uname -n`’s httpd restarted at `(date)`” mail@qq.com exit 1
else
action “httpd is running” /bin/true
exit 0
fi

真正使用时，有些输出是不需要的就去掉
[root@oldboy-B scripts]# cat apachemon1
#!/bin/sh
#created by oldboy 20110523
#QQ 31333741
. /etc/init.d/functions
wget –quiet –spider http://10.0.0.161/index.htm #=====>这个是基于WGET URL方式进行判断
if [ $ -ne 0 ];then
action “httpd is not running” /bin/false >/tmp/httpd.log
httpdctl restart >/dev/null 2>&1
action “httpd is restart” /bin/true >>/tmp/httpd.log
mail -s “`uname -n`’s httpd restarted at `(date)`” 31333741@qq.com exit 1
fi

多条件判断的写法
[root@oldboy-B scripts]# cat apachemon1
#!/bin/sh
#created by oldboy 20110523
#QQ 31333741
. /etc/init.d/functions
HTTPPORTNUM=`netstat -lnt|grep 80|grep -v grep|wc -l`
HTTPPRONUM=`ps -ef|grep http|grep -v grep|wc -l`
wget –quiet –spider http://10.0.0.161/index.htm && RETVAL=$

if [ $RETVAL -ne 0 ] || [ $HTTPPORTNUM -ne 1 ] || [ $HTTPPRONUM -lt 1 ] ;then
#if [ "$RETVAL" != "0" -o "$HTTPPORTNUM" != "1" -o "$HTTPPRONUM" \< "1" ] ;then
action “httpd is not running” /bin/false
action “httpd is not running” /bin/false >/tmp/httpd.log
httpdctl restart >/dev/null 2>&1
action “httpd is restart” /bin/true
mail -s “`uname -n`’s httpd restarted at `(date)`” 31333741@qq.com exit 1
else
action “httpd is running” /bin/true
exit 0
fi