一堆eps文件要将每个文件单独压缩成一个文件,比如a.eps , b.eps, c.eps 压缩成 a.zip ,b.zip ,c.zip for…
April 26, 2015
shell循环,判断介绍,以及实例
shell的循环主要有3种,for,while,until
shell的分支判断主要有2种,if,case
一,for循环
#!/bin/bash for file in $(ls /tmp/test/mytest |grep sh) //for in格式是shell for的基本格式,根js的for in类似 do //循环开始你就把它当成{ echo $file done //循环结束你就把它当成} for ((i=0;i<10;i++)) //注意是双小括号,由于受其他语言的影响,很容易搞错 do echo -n $i done echo //输出换行 for i in 0 1 2 3 4 5 6 7 8 9 do echo -n $i done echo for i in "0 1 2 3 4 5 6 7 8 9" //这个根上面是有区别的,这个循环只循环了一次,双引号里面只是一个变量 do echo -n $i done exit 0
二,while循环
#!/bin/bash i=0 while ((i<10)) do echo $i ((i += 1)) done i=0 while [ $i -lt 10 ] //注意括号内侧二边的空格 do echo $i let "i+=1" //加1 done exit 0
三,until循环
#!/bin/bash END_CONDITION=end until [ "$var1" = "$END_CONDITION" ] //读取的变量根设定的变量相等时退出循环,不然永远循环 do echo "Input variable #1 " echo "($END_CONDITION to exit)" read var1 echo "variable #1 = $var1" echo done exit 0
四,if语句
#!/bin/bash echo "Input a number #1 " read num echo "variable #1 = $num" if [ $num -lt 60 ] //注意lt前面的-,很容易忘的 then echo "you are not pass" elif [ $num -lt 70 ] && [ $num -ge 60 ] //多个条件的判断 then echo "pass" elif [[ $num -lt 85 && $num -ge 70 ]] //如果放在一起,要注意是双方括号,不要写成[ $num -lt 85 && $num -ge 70 ] then echo "good" elif (( $num <= 100 )) && (( $num >= 85 )) //对于有语言基础的人来说,这种写法让人觉得很舒服,不要忘了是双小括号 then echo "very good" else echo "num is wrong" fi //if要有结束标签的,根XML很像,不闭合,就报错 exit 0
五,case语句
#!/bin/sh case $1 in start) echo "start ok" ;; //注意一点,要注意是双分号 stop) echo "stop ok" ;; restart) echo "restart ok" ;; *) echo "no param" ;; esac //注意闭合标签 exit 0 [root@krlcgcms01 forif]# sh c1.sh stop stop ok
作者:海底苍鹰
地址:http://blog.51yip.com/shell/1132.html