Linux Shell Programming Learning Notes--Chapter I.

1. The kernel is placed in the computer's memory from post, until the computer shuts down, the application is placed on the computer's hard disk, and only calls into memory execution when needed.

2.shell is the application, which is the bridge between the kernel and the user program. When the user is logged into the Linux system, the shell is called into memory execution. The relationship of the shell diagram: Lack

3. The user has two ways to open the shell (1) through the graphical interface to operate the Linux operating system

(2) Two software, remote login. The IP login you want to enter is not very clear, enter who IP

4. Differences and connections between scripting languages and compiled languages. Scripting language is easy to learn and difficult to fine.

1.3.1 Basic elements of shell scripts

#！ is the starting symbol for a shell script, a special tag that specifies a file type, which tells the Linux system that the execution of the file requires an interpreter, followed by a path that describes the location of the interpreter in the system.

A command is the most basic element of a shell script, usually consisting of the following three parts. Command name (must have) option parameter

The options and use of the command are placed on the manual page. You can use man [command name] to view

Multiple commands within the same line can be separated by semicolons;

1.3.2 Executing shell scripts

To execute a script first, you must give the current user the right to execute the script file (with x permission not to read it)

First, use the chmod command to assign executable permissions to a script

./[script Name] Execute script file

Linux Shell Programming Learning Notes--Chapter I.