Linux Shell Programming

Shell Programming Concepts

(1) Shell is a command-line interpreter, there are many kinds of shells

(2) The shell as a bridge between the Linux kernel and the user, the user by default cannot directly manipulate the kernel

(3) can be operated through shell Shell, user instructions passed to the shell, passed to the Linux kernel, the kernel accepts to handle

(4) The shell accepts the data returned by the Linux kernel and interprets it as a language that the user can read

(5) The shell is the middle key, the user and the Linux kernel communicates the bridge, the shell kind is many

(6) The various instructions written by the base and shell interpreter are described in this way as parsing with the shell environment, in other words, using the shell environment to write various instructions.

Shell Programming departure

#! bin/bash/

#2017年11月15日14:45:13

#by author Daqi

echo "Hello World"

Executing shell programming

./first.sh

Comments:

If the prompt permission is denied, you can add Chomod o+x first.sh

Shell, shell command, Shell scripting concepts

<1> Shell is the command line interpreter, receives the user input, passes the instruction to the Linux kernel, the kernel returns the data, the shell is the user and the operating system communication bridge

The <2> shell command, which can be seen as a command executed in the shell, is the specific way to compose a shell script

The <3>shell script is made up of multiple shell commands that write multiple shell commands to a file called a shell script

Shell Programming Specification

<1>shell programming files, named in lowercase letters, not recommended for use with numbers

<2>shell script naming is typically named for the functionality that the shell implements

<3>shell Programming files to #! Bash start, followed by Shell type, recommended is Bin/bash

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Linux Shell Programming