Linux Beginner Note five: Bash features in detail! (Video serial number: 03_2,3)

Commands to learn in this section:history,alias,ualias,\cmd

Skills learned in this section:

Features of Bash
Cursor Jump
View command History
The use of command history tips
To alias an order
Command substitution
File name wildcard character

Shell: Shell

Gui:gnome, KDE, XFCE

Cli:sh, CSH, ksh, bash, tcsh, zsh

Process: In each process it appears that only the kernel and the current process exist on the current host

A process is a copy of a program, and a process is a program execution instance

User Working Environment :

Bash:

#: Administrator Command prompt

$: Normal user command prompt

Features of bash:

1. Command history, Command completion

2, Pipeline, redirect

3. Command aliases

4. Command line editing

5. Command line expansion

6. File name Wildcard

7. Variables

8. Programming

command-line editing :

cursor Jump :

Ctrl+ A: Skip to the beginning of the command

ctrl+e: Jump to the end of the command line

ctrl+u: Delete the cursor to the beginning of the command line

ctrl+k: Delete the cursor to the end of the command line

ctrl+l: Clear Screen

Command History :

history: Viewing command Histories

-C: Empty command history

-D OFFSET [n]: Delete command at specified position

-W: Save the Command history to the history file

Environment variables

Path: Command Search Path

Histsize: Command history buffer Size (can be viewed with 'echo $HISTSIZE')

the use of command history tips :

!n: Executes the nth command in the command history;

!-n: Executes the reciprocal nth command in the command history;

!: Executes the previous command;

!string: The most recent command in the command history that starts with a specified string

!$: Reference the last parameter of the previous command, or use "ESC +.";

Text-related commands

View: Cat, TAC, more, less, head, tail

Statistics: WC

Handling: TR, cut, join

Sort by: Sort

Uniq

Command completion, PATH completion

Command completion: The search PATH environment variable specified by each path under the string we give the beginning of the executable file, if more than one, two times tab, you can give a list;

Path completion: Search for each filename under the starting path we give, and try to complement it;

Command Alias

Alias cmdalias= ' COMMAND [options] [arguments] '

Aliases defined in the shell are valid only for the current shell life cycle, and the valid range of aliases is only the current shell process;

Alias: Show commands for all current aliases

ualias cmdalias : Revoke command aliases

　　Typecommand: see if the commands are binding additional parameters

\cmd: Using the original property of the parameter command

command substitution : $ (command), anti-quote: ' command '

To replace a subcommand in a command with the process of executing the result

quotes supported by bash :

": Command substitution

"": weak reference, can implement variable substitution

': Strong reference, do not complete variable substitution

file name wildcard , globbing

*: Any character of any length

?: any single character

[]: matches any single character within the specified range

[ABC], [A-m], [A-z], [A-z], [0-9], [a-za-z], [0-9a-za-z]

[: Space:]: white space character

[:p UNCT:]: Punctuation

[: Lower:]: lowercase letters

[: Upper:]: Uppercase

[: Alpha:]: Uppercase and lowercase letters

[:d igit:]: Number

[: Alnum:]: Numbers and uppercase and lowercase letters

Ways to get these lists: Man 7 glob (I didn't succeed)

[^]: matches any single character outside the specified range

[[: Alpha:]]*[[:space:]]*[[:alpha:]]: Get a file that starts with a letter, ends with a letter, and has spaces in the middle

[[: Alpha:]]*[[:space:]]*[^[:alpha:]]: Get a file that starts with a letter, does not end with a letter, and has spaces in the middle

Practice:

1, create A123, Cd6, c78m, C1 My, m.z, K, 8yu, 789 and other documents; Note that the above files are separated by commas, and the other symbols are part of the file name;

2. Display all files beginning with a or m;

LS [am]*

3. Display all files containing numbers in the file name;

LS *[0-9]*

LS *[[:d igit:]]*

4. Display all files that end with a number and do not contain a blank in the file name;

LS *[^[:space:]]*[0-9]?????????

5. display files with special symbols of non-letters or numbers in the file name;

LS *[^[:alnum:]]*

Linux Beginner Note five: Bash features in detail! (Video serial number: 03_2,3)