【shell】shell编程总结

　　总结一下在写shell脚本时的常见注意事项:

1.shell脚本中的命令最好用命令的全路径，如果不知道全路径可以用which cmd查找命令的全路径。

2.shell脚本中定义环境变量用export xxx=/dir1/dir2.....

3.shell脚本中取变量所以变量前都需加$,或者最好是${变量}

4.掌握常见的if、for、case语法的使用方法

5.shell脚本中最好写清楚注释

6. shell脚本中善于使用函数

7.用 $? 来判断上一个shell命令的执行结果，返回值是0代表正常结束，返回值是其他则代表不正常

8. 将一些命令的执行结果重定向到/dev/null，错误结果也需要重定向到/dev/null (/dev/null是linux的无底洞，我们丢进去的东西就都找不回来了)

9.善于使用ps 加grep命令判断一些服务是否启动，根据是否有相应的进程判断对应的服务是否启动。

10 善于使用awk命令提取一些需要的信息

killUser.sh　　(输入登录的用户名，然后强制退出用户的脚本)

#!/bin/bash

#input username and kill relactive process for kill user

echo "please input username for kill"

read username

#if username is root ,exit

if [ ${username} = 'root' ]

        then

        echo "root can not kill"

        exit

fi

#get user PID

PID=`/usr/bin/ps -aux | /usr/bin/grep qlq | /usr/bin/awk '$1="qlq" {print $2}'`

for killpid in $PID

do

        kill - $killpid

done

echo "killed ok!"

tomcat.sh (测试tomcat服务是否启动，开启、关闭tomcat)

#!/bin/bash

#chkconfig:

#description:tomcat

#input(start stop status) to operate tomcat service

#start funciton(start tomcat service use /opt/apache-tomcat/apache-tomcat-7.0./bin/start.sh)

export CATALINA_HOME=/opt/apache-tomcat/apache-tomcat-7.0.

start(){

        /usr/bin/sh "${CATALINA_HOME}"/bin/startup.sh

        if [ "$?" != "" ]

        then

                echo "service is not success start"

        else

                echo "service is success start"

                                                        fi

        exit

}

#stop function

stop(){

        /usr/bin/sh "${CATALINA_HOME}"/bin/shutdown.sh

        if [ "$?" != "" ]

        then

                echo "service is not success stop"

        else

                echo "service is success stop"

                                                        fi

}

#status function

status(){

        /usr/bin/ps -le | /usr/bin/grep java >/dev/null > /dev/null

        if [ "$?" != "" ]

        then

                echo "service is not start"

        else

                echo "service is running"

                                                fi

}

#read input and dispose function

input=${}

case ${input} in

start)

        start

        ;;

stop)

        stop

        ;;

status)

        status

        ;;

*)

        echo "please use {start to start tomcat,stop to stop tomcat,status to read tomcat status!}"

esac

webmin.ssh (测试webmin服务是否启动、开启、关闭webmin服务)

#!/bin/bash

#start webmin service

start()

{

/etc/webmin/start >/dev/null > /dev/null

if [ $? = '' ]

        then

        echo "webmin is success start"

fi

}

#stop webmin service

stop()

{

/etc/webmin/stop > /dev/null > /dev/null

if [ $? = '' ]

        then

        echo "webmin is success stop"

fi

}

#status webmin

status()

{

   /usr/bin/netstat -ano | /usr/bin/grep  > /dev/null

   if [ $? != '' ]

        then

        echo "webmin is not start"

   else

        echo "webmin is running"

    fi

}

########read input##############

str=$

if [ ${str} = 'start' ]

        then

        start

elif [ ${str} = 'stop' ]

        then

        stop

elif [ ${str} = 'status' ]

        then

        status

else

        echo "please use {start,stop,status}"

fi

addUserBatch.sh (批量添加用户的脚本)

#!/bin/bash

#adduser batch

echo "please input username:"

read username

echo "please input number to create:"

read number

#start to create user

for(( i=;i<="${number}";i++ ))

do

        /usr/sbin/adduser "${username}${i}" > /dev/null > /dev/null

done

#add finished

echo "add OK!"

echo "please input passwd for users"

read password

for(( i=;i<="${number}";i++ ))

do

        /usr/sbin/usermod -p "${password}" "${username}${i}"  > /dev/null > /dev/null

done

delUserBatch.sh (批量删除用户的脚本)

#!/bin/bash

#delete user batch

echo "please input username word to delete"

read word

#get All users like word*

users=`/usr/bin/grep ${word} /etc/passwd | awk -F: -v word1=${word} 'index($1,word1)>0 {print $1}'`

if [ "${users}" = '' ]

 then

        echo "user is does not exist!"

        exit

fi

for username in ${users}

do

        /usr/sbin/userdel -rf ${username} > /dev/null >/dev/null

done

if [ "" = "$?" ]

        then

        echo "delete ok!"

else

        echo "delete failed!"

fi

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【shell】shell编程总结

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