30分钟学习shell常用命令

命令

cat /etc/shells

echo $PATH

echo $SHELL

echo $0 查看当前执行的脚本

可以编写自动化任务，shell脚本

vi hello.sh

#!/bin/bash
echo "hello shell"
date
whoami

添加权限 chmod +x hello.sh

运行：

sh hello.sh 

编程

vi game.sh

猜数字小游戏

#!/bin/bash

echo "input your name:"
#read name
name=$1
channel=$2
echo "hello, $name,welcome to $channel"

使用 bash game.sh 执行

可以使用 echo $name 定义变量，使用 export name=gao 设置为环境变量。重新登录系统后变量值会变为空

*所有的linux文件的隐藏文件都是以.开头

ls /etc/bash
nano .bashrc
#定义参数

Shuf/if/while/random用法

#!/bin/bash

echo "input your name:"
#read name
name=$1
channel=$2
echo "hello, $name,welcome to $channel"
number=$(shuf -i 1-10 -n 1)
echo $number
#while [[ $guess -ne $number ]]
while true
do
echo "please input a number:"
read guess
if [[$guess -eq $number ]]; then
	echo "right,continue?(y/n):"
	read choice
	if [[$choice = "y"]] || [[$choice = "Y"]]; then
		number=$((RANDOM % 10 + 1))
		echo $number
		continue
	else
		break
	fi
elif [[$guess -lt $number]] ; then
	echo "little"
else
	echo "big"
fi
done