Red Flag Linux Desktop 6.0 User manual: Fundamentals of Advanced user usage

Familiarity with the command line interface is significant to the use and management of Linux operating systems. This chapter describes the knowledge of shell operations in the Red Flag Linux http://www.aliyun.com/zixun/aggregation/16493.html >desktop 6.0 system, including file and directory operations, Document and System Management and maintenance, process control, equipment management and other basic content.

8.1.1 Shell Introduction

When a user works at the command line, it does not deal directly with the operating system kernel, but by the command interpreter to accept the command, analyze it, and pass it on to the relevant program. When you enter the Red Flag Linux Desktop 6.0 environment, the system will automatically start the corresponding Shell,shell is a command-line interpreter that provides the interface between the user and the operating system. Red Flag Linux Desktop 6.0 The default shell is bash.

The basic format of the Bash command is as follows:

command name [option] [parameter 1] [parameter 2] ... Where the square brackets enclose the part indicating that the item is optional for the command line.

[Options]: There is a special definition of the command, which starts with "-" and multiple options can be connected by one "-", as LS-A and ls–la mean the same.

[Parameters]: Provides information about the operation of the command, or the name of the file used during the execution of the command. When you enter a username, password, file name, and command name, be sure to be case-sensitive, because uppercase and lowercase letters represent different meanings in the Linux system.

Separate spaces between commands, options, and parameters. A contiguous space is interpreted by the shell as a single space.

Type command

Enter the appropriate command at the shell prompt, and then press ENTER to confirm that the shell reads the command and executes it. If the system does not find the command you entered, it displays: Command not Found, and you need to check that the spelling and capitalization of the typed command is correct.

You can separate two commands with semicolons (;), macro symbols (&), or two consecutive macro symbols (&&). of which ";" and "&" 221

When used, the subsequent command executes regardless of whether the previous command succeeds, and "&&" does not continue after a command fails. This enables you to enter multiple commands on a single line, and commands are executed in the same order as the input order.

Orders are filled.

When the command directory you want to enter is very deep or the file name in the command is very long, just click the <TAB> key, and the system will find the matching entry in the possible command or file name to be automatically padded. If there is more than one file to match the input of the string, can not be filled, you may press the two <TAB> keys, the system will be all the files listed.

Historical records

The shell will remember the input command, just press the UP and DOWN ARROW keys, you can select the command entered.

On this basis, you can run a few simple commands listed below to actually use:

Clear: Refresh Screen

Date: Show dates and times

Echo: Echoes the contents of the command line back to standard output

Cal: Displays the calendar for the specified month or year