Shell Application Tips

1. Press the TAB key for the command to be padded

2, clear or ctrl+l clear screen

3, ctrl+u Delete the command before the cursor

4. History view executed commands

5, the key of the arrow keys can see the executed command

1. Command aliases

Example: Alias COPY=CP//The CP command can be implemented with copy at this time, if the command has parameters, you need to enclose the command in quotation marks

Remove Alias: Unalias alias

2. Input \ Output redirect

(1) Output redirection

Example: Ls-l/tmp >/TMP.MSG//Save the results of the previous command in a later file

LS-L/tmp >>/TMP.MSG//Append the results of the previous command to the following file

(2) Input redirection

Example: Wall </etc/filename to broadcast the information in filename '

(3) Error redirection

Syntax:2> error output redirect, 2 is the file identifier of the standard error output

Example: Cp-r/usr/backup/usr.bak 2>/bak.error command execution error message saved to Bak.error file

3. Pipeline

Sends the output of one command to another command as input to another command

Grammar:

Command 1| command 2....| Command n

Instance:

Ls-l | More

Ls-l/etc | grep Init

4. Command connector

(1):

Each command executes sequentially in sequence.

(2) &&

There is a logic and relationship between the execution of the preceding command, and the subsequent command executes when the previous command executes successfully.

(3) | |

The execution of the previous command has a logical or relationship, and when the first command executes successfully, the second command is not executed; the second command executes when the first command fails

5. Command substitution

To use the output of one command as a parameter to another command

Syntax: Command 1 ' command 2 '//is not a single quotation mark, is the left side of the keyboard 1 small apostrophe; At this point, the output of command 2 as a parameter of command 1

Shell Application Tips