Shell BASICS (1) starting from Hello World

Note: Here are the shell notes I made. Next, we will provide a series of notes.

Shell is a scripting language, so there must be an interpreter to execute these scripts. Common shell script interpreters in Unix/Linux include bash, sh, CSH, and KSh. They are used to being called a shell. We often talk about the number of shell types. In fact, it refers to the shell script interpreter.

As for the introduction and differences between these script interpreters, I am not clear about them. I should check the information myself. In fact, it is not very important to know whether or not I know it. This does not affect whether you can use shell.

1. Create a new file, such as lottu01.sh, with the extension SH (SH stands for shell). The extension does not affect script execution. Let's start with "Hello World.

#!/bin/bashecho "hello world !"

Note: "#!" Is an agreed tag, which tells the system what interpreter is required to execute this script, that is, which shell is used. Use bash.
Echo: Is the output command in shell, and outputs the string following it to the screen. -- This is also known to all.

2. Run the script

$ Chmod + x lottu01.sh # grant the script execution permission $./lottu01.shhello world!

Note that you must write it as./test. Sh instead of test. Sh.

Write test directly. sh, the Linux system will go to the path to find whether it is named test. sh, and only $ home/bin, $ home/sbin,/usr/bin,/usr/sbin and so on are in the path. Your current directory is usually not in the path, therefore, it is written as test. sh cannot find the command. /test. sh tells the system to find it in the current directory.
Of course, you can also write test. Sh. Perform the following operations:
CP lottu01.sh ../bin/# ../bin is under the bin of the home directory of the current user. Don't misunderstand this.
Then test whether lottu01.sh is OK.

$cp lottu01.sh ../bin/$ lottu01.sh hello world !

3. read command

ECHO is the output in shell, So input. Read. -- This will be explained in detail in later sections -- read.

#! /Bin/bash # Author: lottu # copyright (c) li0924 # Start scriptecho "Please input your name? "Read nameecho" Hi, $ {name} "test: $ chmod + x lottu02.sh $./lottu02.sh please input your name? Lottu -- name you entered here. Hi, lottu

[Note]

1. The first line of the script -#! /Bin/Bash; it is the interpreter of the script. Of course, you can leave it empty. At that time, you must execute it like this.
/Bin/bash script;
2. Echo, READ command; this will be added later.

Shell BASICS (1) starting from Hello World