shell的case语句

case语句格式

# vi test.sh

:

echo "input : "

read num

echo "the input data is $num"



case $num in

1) echo "January";; 双分号结束

2) echo "Feburary";;

5) echo "may" 每个case可以有多条命令

echo "sdfd"

echo "sdf";; 但最后一条命令一定是双分号结束



*) echo "not correct input";; *）是其他值、default的意思



esac

# sh ./test.sh

input :

2

the input data is 2

Feburary



# sh ./test.sh

input :

ter

the input data is ter

not correct input

case 语句如果某个选项没有任何语句，也要加;; 否则会出下边错误

test: line 166: syntax error near unexpected
token `)'

test: line 166: `"system hostname config")'

匹配符[]是专门针对单字符的值,如果用[no],就是n和o之一

case $yn in

[no]) return 1;;

* ) echo "only accept Y,y,N,n,YES,yes,NO,no" >&2;;

[macg@mac-home ~]$ sh test.sh

enter y/n :

no

only accept Y,y,N,n,YES,yes,NO,no

改正

case $yn in

no) return 1;;

NO) return 1;;

* ) echo "only accept Y,y,N,n,YES,yes,NO,no" >&2;;

esac

[macg@mac-home ~]$ sh test.sh

enter y/n :

no

注意：：

如果有多个单词可以用"|"隔开，如

case $yn in

start | begin ) return 0;;

end | over ) return 1;;

* ) return 3;;

if, case，匹配字符串最常见，但如何匹配一段很长的输出，一堆文字？最好方法，用“*”，如：*"command not found"*

[macg@machome ~]$ vi test.sh



var=$(ls -l $1)
$()取命令输出，$1是命令行参数

echo "output is $var"



case $var in

"-rw-rw-r--"*) echo "this is not a execute file";;

"-rwxrwxr-x"*) echo "this is a execute file";

注意*在双引号外边

esac

[macg@machome ~]$ sh test.sh 22.txt

output is -rw-rw-r-- 1 macg macg 15 Jun 9 19:00 22.txt

this is not a execute file



[macg@machome ~]$ chmod +x 22.txt

[macg@machome ~]$ sh test.sh 22.txt

output is -rwxrwxr-x 1 macg macg 15 Jun 9 19:00 22.txt

this is a execute file

这里需要注意的是：$(ls -l $1)
$()取命令输出

匹配是用两个**，因为整个var的内容是一行，要在两个之间匹配

例2．匹配file命令输出的一堆文字,以获知文件类型

用’ ’ 取输出,然后用CASE+*对输出做修饰处理.

var=`file $1` `
`和$( )作用相同，是取命令输出

echo "output is $var"



case $var in

"$1: ASCII text"*) echo "this is a text file";;

"$1: directory"*) echo "this is a directory";;

注意*在双引号外边

esac

[macg@machome ~]$ sh test.sh 22.txt

output is 22.txt: ASCII text

this is a text file



[macg@machome ~]$ sh test.sh test-dir

output is test-dir: directory

this is a directory

最典型的shell case命令匹配命令行，用于sys v启动脚本的start|stop|restart|status处理

case "$@" in

($@ 字符串数组：以"参数1" "参数2" ... 的字符串数组形式保存所有参数

对于单个参数的情况，$@就是一个字符串)



start)

echo -n "Starting
firewall..."

。。。

echo "OK!"

exit 0

;;

stop)

echo -n "Stopping
firewall..."

。。。

exit 0

;;

restart)

$0
stop $0即执行原始程序

$0
start

;;

status)

clear

echo ">------------------------------------------"


iptables -L

echo ">------------------------------------------"


iptables -t nat
-L POSTROUTING

exit 0

*)

echo "Usage: $0
{start|stop|restart|status}"

exit 1

esac