Shell for循环和select循环语句 for循环格式for 变量名 in 变量取值列表 do 指令 done示例打印5 4 3 2 1 5个数字#!/bin/bash for i in 5 4 3 2 1 do echo $i done 方法二 #!/bin/bash for (( i=5;i>0;i--)) do echo $i done PS:改名命令rename命令jpg格式的图片改成pngrename ".jpg" ".png" "*.jpg"打印九九乘法表#!/bin/bash for num1 in `seq 9` do for num2 in `seq 9` do if [ $num1 -ge $num2 ];then if ((($num1*$num2)>9)) ;then echo -en "${num1}x${num2}=$((num1*num2)) " else echo -en "${num1}x${num2}=$((num1*num2)) " fi fi done echo " " done计算1-100的和#!/bin/bash for ((i=1;i<=100;i++)) do ((sum=sum+$i)) done echo "$sum"select循环语句select 变量名 [ in 菜单取值列表] do 指令 done示例:select 循环打印简单菜单项 1、直接使用列表字符串#!/bin/bash select name in zhansan lisi wanger do echo $name done2、采用数组作为变量打印#!/bin/bash array=(zhansan lisi wanger) select $name in "${array[@]}" do echo "$name" done#!/bin/bash PS3="please select a num from menu:" #PS3是select循环的提示符 select name in zhansan lisi wanger do echo -e "I guess you selected the menu is:\n $REPLY) $name" #REPLY变量是菜单项对应的数字 done示例打印选择菜单 ，选择一键安装不同Web服务1.[install lamp] 2.[install lnmp] 3.[exit]#!/bin/bash RETVAR=0 path=/server/scripts #定义脚本路径 [ ! -d "$path" ] && mkdir $path -p #如果不存在就创建 function Usage() { echo "Usage :$0 argv" return 1 } function InstallService() { if [ $# -ne 1 ]; then Usage fi local RETVAR=0 echo "start installing ${1}." sleep 2 if [ ! -x "$path/${1}.sh" ]; then echo "$path/${1}.sh 没有执行权限" return 1 else $path/${1}.sh return $RETVAR fi } function main() { PS3="please input the num you want:" select num in "Install lamp" "Install lnmp" "exit" do case "$num" in "Install lamp") InstallService lamp RETVAR=$? ;; "Install lnmp") InstallService lnmp RETVAR=$? ;; exit) echo bye. return 3 ;; *) echo "the num you input must be {1|2|3}" echo "Input error" esac done echo $ RETVAR } main