case 條件判斷

case語句的語法格式：

case expression in

pattern1)

   suite1

   ;;

pattern2)

   suite2

   ;;

...

patternn)

   suiten

   ;;

*)

   other_suite

   ;;

esac

一、編寫一個測試腳本，名字為myservice.sh

根據輸入的選項，創建相應的文件

#/bin/bash
#
myService=`basename $0`
lockFile="/var/lock/subsys/$myService"

[ $# -lt 1 ] && echo "Usage: $myService {start|stop|restart|status}" && exit 4

case $1  in
'start')
        touch $lockFile
        echo "Starting $myService OK"
        ;;
'stop')
        rm -f $lockFile
        echo "Stopping $myService OK"
        ;;
'restart')
        rm -f $lockFile
        touch $lockFile
        echo "Restarting $myService OK"
        ;;
'status')
        if  [ -f $lockFile ];then
                  echo "$myService is runing"
        else
                  echo "$myService is stopped"
        fi
        ;;
*)   
        echo "Usage: $myService {start|stop|restart|status}"
        exit 3

esac

執行腳本：

[root@192 src]# ./myservice.sh

Usage: myservice.sh{start|stop|restart|status}

[root@192 src]# ./myservice.sh status

myservice.sh is stopped

[root@192 src]# ./myservice.sh start

Starting myservice.sh OK

[root@192 src]# ./myservice.sh status

myservice.sh is runing

[root@192 src]# ./myservice.sh stop

Stopping myservice.sh OK

[root@192 src]# ./myservice.sh restart

Restartingmyservice.sh OK

二、練習：寫一個腳本

1、提示用戶輸入一個任意字符

2、能判斷此字符是數字、字母或特殊字符

vim user.sh

#!/bin/bash

#

while true;do

read -p " Enter a char: " char

[[ "$char" == 'quit' ]]&& break

case $char in

[a-z])

      echo "word"

      ;;

[0-9])

       echo "digital"

      ;;

*)

      echo "special"

      ;;

esac

done

腳本執行結果：

[root@192 src]# ./user.sh

 Enter a char: 9

digital

 Enter a char: a

word

 Enter a char: > 

special

 Enter a char: quit

[root@192 src]#

三、練習：寫一個腳本，能對/etc/目錄進行打包備份，備份位置為/backup/etc-日期.后綴

1、顯示如下菜單給用戶：

xz) xz compress

gzip) gzip compress

bip2) bzip2 compress

2、根據用戶指定的壓縮工具使用tar打包壓縮

3、默認為xz：輸入錯誤則需要用戶重新輸入

[root@192 src]# cat backup.sh

#/bin/bash

#

[ -d /backup ] || mkdir /backup

cat << EOF

Please choose a compress tool：

xz) xz compress

gzip) gzip compress

bzip2) bzip2 compress

EOF

while true; do

   read -p "Your option: " option

   option=${option:-xz}

   case $option in

   xz)

     compressTool='J'

     suffix='xz'

     break ;;

   gzip)

     compressTool='z'

     suffix='gz'

     break ;;

   bzip2)

     compressTool='j'

     suffix='bzip2'

     break ;;

   *)

    echo "wrong option."

    ;;

   esac

done

tar ${compressTool}cf /backup/etc-`date+%F-%H-%M-%S`.tar.$suffix /etc/*

腳本執行結果：

[root@192 src]# ./backup.sh

Please choose a compress tool：

xz) xz compress

gzip) gzip compress

bzip2) bzip2 compress

Your option: xz

tar: 從成員名中刪除開頭的“/”

[root@192 src]# cd /backup/

[root@192 backup]# ls

etc-2016-08-13-22-46-26.tar.xz 

可以看到已經按照要求生成相應的備份文件。

四、練習：寫一個腳本，完成如下功能

說明：此腳本能夠為指定網卡創建別名、指定地址；使用格式：mkethalias -v| --verbose -i ethx

1、-i選項用于指定網卡

2、如果網卡存在：在命令行，請用戶指定一個別名

3、讓用戶指定IP和掩碼

4、用戶可以同時使用-V或--verbose選項：如果使用了，顯示配置結果：否則，則不予顯示

vim  scriptargs.sh

#/bin/bash

#

debug=0

while [ $# -ge 1 ];do

  case $1 in

   -i|--interface)

    ethcard="$2"

    shift 2

    ;;

   -v|--verbose)

    debug=1

    shift

    ;;

   *)

    echo "Wrong options arguments."

    echo "Usage: `basename $0` [-v|--verbose] -i|--interfaceInterface"

    shift $#

    ;;

  esac

done

#echo "Interface: $ethcard, VerboseFlag: $debug "

! ifconfig $ethcard &> /dev/null&& echo "No this interface ..." && exit 3

read -p "Enter an alias: "ethAlias

read -p "Enter IP: " ipAddr

read -p "Mask: " netMask

ifconfig $ethAlias $ipAddr netmask $netMask

[ $debug -eq 1 ] && ifconfig$ethAlias

執行結果：

[root@192 src]# vim scriptargs.sh -i eth0

[root@192 src]# ./scriptargs.sh -i eth0

Enter an alias: eth0:2

Enter IP: 192.168.1.5

Mask: 255.255.255.0

[root@192 src]# ifconfig

eth0     Link encap:Ethernet  HWaddr00:0C:29:D9:A2:5D 

         inet addr:192.168.10.102 Bcast:192.168.10.255 Mask:255.255.255.0

         inet6 addr: fe80::20c:29ff:fed9:a25d/64 Scope:Link

         UP BROADCAST RUNNING MULTICAST MTU:1500  Metric:1

         RX packets:16489 errors:0 dropped:0 overruns:0 frame:0

         TX packets:8692 errors:0 dropped:0 overruns:0 carrier:0

         collisions:0 txqueuelen:1000

         RX bytes:1345332 (1.2 MiB)  TXbytes:945356 (923.1 KiB)

eth0:2   Link encap:Ethernet  HWaddr00:0C:29:D9:A2:5D 

         inet addr:192.168.1.5 Bcast:192.168.1.255 Mask:255.255.255.0

         UP BROADCAST RUNNING MULTICAST MTU:1500  Metric:1

lo       Link encap:Local Loopback 

         inet addr:127.0.0.1 Mask:255.0.0.0

         inet6 addr: ::1/128 Scope:Host

         UP LOOPBACK RUNNING MTU:65536  Metric:1

         RX packets:0 errors:0 dropped:0 overruns:0 frame:0

         TX packets:0 errors:0 dropped:0 overruns:0 carrier:0

         collisions:0 txqueuelen:0

         RX bytes:0 (0.0 b)  TX bytes:0(0.0 b)