Linux Common Commands (second Edition)--shell application tips

ShellApplication Tips

Tips:

1, command completion function:<Tab> Key

2, clear screen:ctrl+l

3. Delete all contents before cursor:ctrl+u

4. Command history: Historical

Then:! History The command label listed, you can execute that command.

Such as:! 188

Also: Press the arrow keys ↑ and ↓ to find previously executed commands.

Key Tips:

1. Command aliases:

Role: Can make the operation easier, commands can be more easily remembered.

Alias: Displays the aliases that have been defined by the system.

Define aliases:

Alias COPY=CP

Alias drm= "Rm-rf" #定义别名组合, you must use " " to draw up

To delete an alias :

Unalias copy

Attached-many times, systems in UNIX systems do not have these aliases set up!

2. Input/Output redirection:

0 (STDIN)-Standard input, keyboard ;

1 (STDOUT)-standard output, display ;

2 (STDERR)-standard error output, monitor.

> or >> output redirection

LS-L/tmp > test.txt// file original content empty

LS-L/tmp >> test.txt// append

< input redirection

Wall < Test.txt// input REDIRECT

2> Error Output redirection

Cp-r/usr/backup/usr.bak 2>/bak.error

3, Pipeline : The output of one command is passed to another command as input to another command.

Ls-l/etc | More

Ls-l/etc | grep init #grep Init/etc/inittab

Ls-l/etc | grep init | Wc-l #wc command is a counter

4. Command Connector

1); #用; each command in the interval is executed sequentially

PWD, ls;d ate

2)&&

Command1 && Command2

Successful execution

Failure does not execute

#前后命令的执行存在逻辑与关系, only the command after && has been successfully executed before it is executed.

e.g.

Write Mary

LS && pwd

LSKKK && pwd

3)| |

Command1 | | Command2

Execution does not execute

Do not perform execution

#前后命令的执行存在逻辑或关系, only | | after the previous command failed to execute , the command behind it will be executed.

e.g.

Write Mary

ls | | Pwd

LSKKK | | Pwd

For more information, please refer to another series of blogs-the four-day Shell Programming Series:

http://blog.csdn.net/zjf280441589/article/details/17455515

http://blog.csdn.net/zjf280441589/article/details/17467069

http://blog.csdn.net/zjf280441589/article/details/17487351

http://blog.csdn.net/zjf280441589/article/details/17503985

5. Command substitution

Command 1 ' command 2 '# simplifies the operation by making the output of command 2 a parameter of command 1 .

E.g.ll ' which touch ' # See The details of the touch command

Attached-cat/etc/shells# lists all shells supported by the current system

And the Linux default is bash/bin/bash

A bit older UNIX bin/sh

Attached-WC

Wc-l msg# View msg file content how many lines

Linux Common Commands (second Edition)--shell application tips