Linux Learning –shell Scripts

The shell is a bridge between command and hardware.

The shell works in two ways: interactive, batch disposition

Interactive: A user enters a command at a time, the shell translates and executes a

Batch processing: The user makes multiple commands into a shell script, the shell executes all commands at once when executing the script, and theshell script is a program that combines the various commands into logical statements

1. View all the available shell interpreters in the system

Cat/etc/shells

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2. View the current Shell interpreter

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3. Write a simple shell script

Mainly used in the text Editor VI, according to the order of execution sequence, write a Linux command per line

A complete Linux script should contain: script declaration, comment information, executable statement (Linux command)

Script Declaration (#! ): Tells the system which shell interpreter the command should use

Note Information (#): to the executable statement or program functions, you can omit

Executable statement: composed of command line

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4. How to execute Scripts

A, script file path

b, SH script file path

C, source script file path

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5, the parameters of the receiving user

Shell in order to allow users more flexibility to complete the work, you can accept the user input parameters, the script can be followed by user input parameters

From the first to the back in turn $1,$2,$3 ....

$ A program title of the current execution script

$1-9,${10},${11},... The positional variable of the parameter that represents the position of the parameter

$# altogether has several parameters

$* value of all positional variables

$? Determine whether the previous command can perform a victory, 0 means victory, or 0 means failure

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Original link: http://www.magedu.com/71943.html

This article is from the "Marco Linux Training" blog, so be sure to keep this source http://mageedu.blog.51cto.com/4265610/1931066

Linux Learning –shell Scripts