Shell编程笔记---循环操作

循环操作
` 是tab键上面的那个符号

一、for循环

格式：

for 变量名 in 列表do   命令done

-------------例子------------------


循环当前目录文件

for loop in `ls `do   echo $loopdonefor loop in 1 2 3 4 5 6do   echo $loopdonefor loop in a b c ddo   echo $loopdone

分别打印1-6，a-d

二、while循环

while 条件 do   命令done

#!/bin/shcount=0while [ $count -lt 5  ]do        count=`expr $count + 1`        echo $countdone无限循环while:do done

===========例子2从文件中读取内容=================
文件feifei.txt
内容 
feifei:info:1
beibei:develope:2
meimei:pc:3
-----------------------------

while read line do  echo $linedone < feifei.txt

方式2用IFS读文件，去除冒号

IFSBAK=$IFSIFS=:while read NAME DEPT IDdo        echo -e "$NAME\t $DEPT\t $ID"done < feifei.txtIFS=IFSBAK

=============================================


跳出循环
break
continue


===============选择菜单=========================

#!/bin/shwhile :doclearcat << feifei----------------------------        1:select red        2:select blue        3:select exit----------------------------feifeiecho -n -e "choice your color: "read choice        case $choice in        1) echo "red" ;;        2) echo "blue" ;;        3) echo "byebye"                exit 0 ;;        *) exit 0 ;;        esac        echo "press any key continue"        read DUMMYdone

=====================================================


格式化输入内容
command << word 
any input
word
如：（分界符feifei,不要有空格）
cat << feifei
----------------------------
        1:select red
        2:select blue
        3:select exit
----------------------------
feifei