Linux Common Commands (second Edition)--shell application 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:! The command label listed in history, 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, must be caused by ""

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 contents 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 execution fails , the command after it is executed.

e.g.

Write Mary

ls | | Pwd

LSKKK | | Pwd

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