linux运维初级班shell脚本编程测试及参考答案

shell脚本编程实战模拟考试题（上机）

一、考试前准备工作：

1.执行yum install httpd -y 安装httpd。

2.检查安装情况

[root@oldboy-B tmp]# rpm -qa httpd

httpd-2.2.3-45.el5.centos.1

3.启动httpd，并检查

[root@oldboy-B tmp]# /etc/init.d/httpd start

启动 httpd：[确定]

[root@oldboy-B tmp]# netstat -lnt|grep 80 #==>检查端口

tcp 0 0 :::80 :::* LISTEN

[root@oldboy-B tmp]# ps -ef|grep httpd#==>检查进程

root 4041 1 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4043 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4044 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4045 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4046 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4047 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4048 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4049 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

apache 4050 4041 0 14:24 ? 00:00:00 /usr/sbin/httpd

root 4061 3793 0 14:25 pts/0 00:00:00 grep httpd

二、上机考试要求:

1.开发shell脚本/server/scripts/httpdctl，实现通过脚本httpdctl来控制apache服务的启动，停止，

重起。启动时命令要求：httpdctl start|stop|restart

提示：需要将httpdctl路径加到系统全局环境变量里。

参考答案：

[root@oldboy-B scripts]# pwd

/server/scripts

a.if语句实现：

[root@oldboy-B scripts]# cat httpdctl

#!/bin/sh

#created by oldboy 20110523

#QQ 31333741

if [ "$1" = "start" ];then

/etc/init.d/httpd $1 >/dev/null 2>&1

echo "启动 httpd：[确定]"

elif [ "$1" = "stop" ];then

/etc/init.d/httpd $1

elif [ "$1" = "restart" ];then

/etc/init.d/httpd $1 >/dev/null 2>&1

echo "重起 httpd: [确定]"

else

echo "用法： $0 {start|stop|restart}"

exit 1

fi

提示：这个问题用case语句实现效果更佳。 本文因学生还未讲解到case.

[root@oldboy-B scripts]# echo 'export PATH=/server/scripts:$PATH' >>/etc/profile

#===>将httpdctl路径加到系统全局环境变量里。

[root@oldboy-B scripts]# source /etc/profile

#===>使httpdctl路径加到系统全局环境变量生效

[root@oldboy-B scripts]# which httpdctl

/server/scripts/httpdctl

[root@oldboy-B scripts]# httpdctl stop

停止 httpd：[确定]

[root@oldboy-B scripts]# httpdctl start

启动 httpd：[确定]

[root@oldboy-B scripts]# httpdctl restart

重起 httpd: [确定]

-------------------------------------------------------

b.把相同的路径用变量替换[脚本改进]

[root@oldboy-B scripts]# cat httpdctl

#!/bin/sh

#created by oldboy 20110523

#QQ 31333741

HTTPDPATH=/etc/init.d/httpd

if [ "$1" = "start" ];then

$HTTPDPATH $1 >/dev/null 2>&1

echo "启动 httpd：[确定]"

elif [ "$1" = "stop" ];then

$HTTPDPATH $1

elif [ "$1" = "restart" ];then

$HTTPDPATH $1 >/dev/null 2>&1

echo "重起 httpd: [确定]"

else

echo "用法： $0 {start|stop|restart}"

exit 1

fi

-------------------------------------------------------

c.调用系统函数functions，实现更专业友好的提示[继续脚本改进]

[root@oldboy-B scripts]# cat httpdctl

#!/bin/sh

#created by oldboy 20110523

#QQ 31333741

. /etc/init.d/functions

HTTPDPATH=/etc/init.d/httpd

if [ "$1" = "start" ];then

$HTTPDPATH $1 >/dev/null 2>&1

action "启动 httpd:" /bin/true

elif [ "$1" = "stop" ];then

$HTTPDPATH $1

elif [ "$1" = "restart" ];then

$HTTPDPATH $1 >/dev/null 2>&1

action "重起 httpd:" /bin/true

else

echo "用法： $0 {start|stop|restart}"

exit 1

fi

提示：注意action "启动 httpd:" /bin/true的用法

[root@oldboy-B scripts]# httpdctl stop

停止 httpd：[确定]

[root@oldboy-B scripts]# httpdctl start

启动 httpd: [确定]

[root@oldboy-B scripts]# httpdctl restart

重起 httpd: [确定]

-------------------------------------------------------

d.case语句实现方式

[root@oldboy-B scripts]# cat httpdctl

#!/bin/sh

#created by oldboy 20110523

#QQ 31333741

. /etc/init.d/functions

HTTPDPATH=/etc/init.d/httpd

case "$1" in

start)

$HTTPDPATH $1 >/dev/null 2>&1

action "启动 httpd:" /bin/true

;;

stop)

$HTTPDPATH $1

;;

restart)

$HTTPDPATH $1 >/dev/null 2>&1

action "重起 httpd:" /bin/true

;;

*)

echo "用法： $0 {start|stop|restart}"

esac

e.更专业的实现方法

[root@oldboy-B scripts]# cat httpdctl

#!/bin/sh

#created by oldboy 20110523

#QQ 31333741

[ -f /etc/init.d/functions ] && . /etc/init.d/functions

start() {

daemon httpd >/dev/null 2>&1

RETVAL=$?

action "启动 httpd:" /bin/true

return $RETVAL

}

stop() {

killproc httpd >/dev/null 2>&1

[ $? -eq 0 ] && action "停止 httpd:" /bin/true

}

case "$1" in

start)

start

;;

stop)

stop

;;

restart)

$0 stop

$0 start

;;

*)

echo "usage: $0 {start|stop|restart}"

esac

exit $RETVAL

f.系统自带的才是最好的。

请less /etc/init.d/httpd

要求：请所有同学用中文注释httpd脚本每一行，不会的可以咨询老师。

##############################################################

##############################################################

2.开发shell脚本apachemon，实现通过该脚本定时(每隔5分钟)监控http服务的运行状态，如果未运行则自动

调用httpdctl启动http服务，并发送mail通知系统管理员。

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

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 </tmp/httpd.log

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 #=====>正式运行，最好注释掉

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 </tmp/httpd.log

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 </tmp/httpd.log

exit 1

fi

提示:请同学们详细总结wget命令，做为下周作业提交。

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

#提示：以上是两个if为多条件判断的写法，建议同学们掌握第一个。

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 </tmp/httpd.log

exit 1

else

action "httpd is running" /bin/true

exit 0

fi

以上为 老男孩 给的课前考试的参考答案，欢迎大家讨论、交流，共同提高进步。

后记：shell编程能力 是衡量linux运维工程师水平的一个重要砝码，因此，必须要掌握它。。

本文出处/article/4130440.html ，作者：老男孩 。