linux shell 脚本基础编写

输出hello world 

vi test1

vi界面中编写shell,必须以#! /bin/sh开头

#! /bin/sh

$i="Hello World"

echo "$i"

保存退出

chmod 777 test1

./test1 查看是否输出Hello World

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查看shell的目录是否为/bin/bash

vi test2

vi编辑

#! /bin/sh

if [ "$SHELL"="/bin/bash" ];then echo "your SHELL src is /bin/sh"

else

echo "your SHELL src $SHELL"

fi

同样执行 chmod 777 test2  接着./test2

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vi test3

vi 编辑

#! /bin/sh

mailfolder=/root/Desktop/mailfile

[ -r "$mailfolder"] || { echo "can not read $mailfolder ";exit 1; }

content=`cat $mailfolder` && content="${content#From}"

echo "$mailfolder has mail from : $content"

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vi test4

vi 编辑

#! /bin/sh

in="$1"

case "$1" in

*1*)

echo "input has 1" ;;

*2*)

echo "input has 2" ;;

*3*)

echo "input has 3" ;;

*)

echo "input has $1" ;;

esac

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