Linux系列之Shell脚本

概述：shell常用代码总结

helloword入门

#!/bin/bash  
# 指定解析器

echo "helloworld"
echo $A

多命令处理

#!/bin/bash

# 多个命令
cd /home/machine/file
touch "f01d02.txt"
echo "hello BD" >> f01d02.txt

shell变量

#!/bin/bash

# 0是$0 代表该脚本名称，$1-$9 代表第一到第九个参数，十以 上的参数，十以上的参数需要用大括号包含，如${10}
echo "A $0 $1 $2"
# 获取所有输入参数个数
echo $#

# 代表命令行中所有的参数
echo $*
echo $@

if 判断

demo1

#!/bin/bash

if [ $1 -eq "1" ]
then
	echo "hello A"
elif [ $1 -eq "2" ]
then
	echo "hello B"
fi

demo2

#!/bin/bash

if [ -f $1 ]
then 
	echo "文件存在!"
else
	echo "文件不存在!"
fi

case 语句

#!/bin/bash
case $1 in
"1")
	echo "hello A"
;;

"2")
	echo "hello B"
;;

*)
	echo "no"
;;

esac 

for 循环

demo1

#!/bin/bash

# 从1加到100
s=0
for((i=1;i<=100;++i))
do
	s=$[ $s + $i ]
done

echo $s 

demo2

#!/bin/bash

# 打印所有输入参数
for i in $*
do
	echo "hello $i"
done

for i in "$*"

do
        echo "hello $i"
done

for i in $@
do
        echo "hello $i"
done

for i in "$@"
do
        echo "hello $i"
done

while 循环

#!/bin/bash

# 从1加到100
s=0
i=0
while [ $i -le 100 ]
do
	s=$[ $s + $i ]
	i=$[ $i + 1 ]
done

echo $s

read 读取控制台输入

#!/bin/bash
read -t 7 -p "Enter your name in 7 seconds: " NAME
echo $NAME 

函数

#!/bin/bash

# 计算两个输入参数的和

function sum(){
	s=0
	s=$[ $1 + $2 ]
	echo "$s"
}

read -p "Please input the number1: " n1
read -p "Please input the number2: " n2

sum $n1 $n2

shell工具

包括：cut、sed、awk、sort

$ cut -d " " -f 1 cut.txt
$ sed -e '2d' -e 's/wo/ni/g' sed.txt
$ wk -F : 'BEGIN{print "user, shell"} {print $1","$7} END{print "dahaige,/bin/zuishuai"}' 
$ sort -t : -nrk 3 sort.sh