13th Chapter Learning Shell Script

First Script

[email protected] script]# cat-N sh01.sh1#!/bin/Bash2#Program:3#This program Shows"Hello world!" inchyour screen. 4Path=/usr/local/java/jdk1.8.0_91/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin:/root/bin:~/bin5export PATH; 6Echo-e"Hello world! \a \ n"     7Exit0

First line: #! /bin/bash declares the shell name used by this script

Line 23rd: Comments

Row four: The declaration of an environment variable so that the program executes some external commands without having to write an absolute path

Line five: Make the environment variable effective

Line Six: Main program section

Line seventh: Use the exit command to break the program and return a value to the system, after executing the script, use echo $? To get the value.

[email protected] script]# VI sh01.sh[[email protected] script]#. /Sh01.shhelloworld!  // View the value returned to the system by the script above [[email protected] script]# echo $? 0

a simple shell script exerciseInteractive Scripting: variable content is determined by the user

[email protected] script]# cat-N sh02.sh1#!/bin/Bash2Path=/usr/local/java/jdk1.8.0_91/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin:/root/bin:~/bin3Export PATH4         5Read-p"Please input your first name:"FirstName #tell user to input their name6Read-p"Please input your last name:"LastName7Echo-e"\ Your Full name is: $firstname $lastname"[email protected] script]# sh sh02.shplease input your first name:wuplease input your last Name:chao your full name /c5> is: Wu Chao[[email protected] script]#

change with Date: Create a file with a date

//Viewing script Scripts[email protected] script]# cat sh03.sh#!/bin/Bashpath=/usr/local/java/jdk1.8.0_91/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin:/root/bin:~/Binexport Pathecho-E"I'll use the ' touch ' command to create 3 files."Read-P"Please input your file name:"Fileuserfilename=${fileuser:-"filename"}date1=$ (date-d -2day +%y%m%d) Date2=$ (date-d -1day +%y%m%d) Date3=$ (Date +%y%m%d) File1=${filename}${date1}file2=${filename}${date2}file3=${filename}${date3}touch"$file 1"Touch"$file 2"Touch"$file 3"//Execute the Script[[email protected] script]# sh Sh03.shi would use'Touch'command to create3files.please Input your file Name:testfile[[email protected] script]#//View Results[Email protected] script]# ls-l testfile*-rw-r--r--.1Root root0July +  A: +testFile20160717-rw-r--r--.1Root root0July +  A: +testFile20160718-rw-r--r--.1Root root0July +  A: +Testfile20160719[[email protected] script]#

Note: $ () is the result of executing the code inside. ${} takes the value of the variable.

Numeric Operations

[email protected] script]# cat sh04.sh#!/bin/Bashpath=/usr/local/java/jdk1.8.0_91/bin:/usr/local/bin:/usr/local/sbin:/usr/bin:/usr/sbin:/bin:/sbin:/root/bin:~/Binexport Pathecho-E"Please input the numbers:"Read-P"First number :"N1read-P"Second Number:"N2total=$ (($n 1*$n 2)) Echo-E"\ n The result of $n 1 * $n 2 is ==> $total"[[ Email protected] script]# [[email protected] script]# sh sh04.shplease input ' numbers:first number: ASecond Number: atThe result of A* at  is==>276[email protected] script]#

var=$ (OP content)

Used to calculate

[[email protected] script]# echo $ ((3))

13th Chapter Learning Shell Script