"Linux Basics" linux basic command line learning notes

Absolute path: Cd/home/python
Relative path: CD Downloads

. Expression: Current that path
.. Represents: The previous layer of the current path
.. /.. Represents: The top two level of the current path

No... or more of

Is_
LS View the file under the current path and the name of the folder
Ls/bin: See what's Under the Bin folder in the root directory
LS Documents: View everything under the Documents folder under the current path

LS *: * denotes any number of characters, or can not

? Represents a character, there must be 1, cannot have no

[xn] means: any one of the characters in brackets
[ABCdef] can be written as [A-f]: represents any one character from a to F

-A hidden file
-l list Display style
-H Mate-L displays a reasonable size unit

Cd:
CD desktop into the Desktop folder

The name of the CD folder

Cd.. Jumps to the previous level of the current path

CD-Jump to the last path (similar to the one seen in the TV remote)

CD ~ Jump to the current user's home directory (/home/python)

PWD: Shows the path of the current operation (absolute path/AAA/BB/CC)

Clear: Clear Screen

TAB key: Used to auto-complete

Touch: Create a file that does not have a suffix in Linux, all filenames are custom

Redirect:

ls > Test.txt: Writes the information that was originally displayed on the terminal to the Test.txt file

The difference between >> and > is that:>> is added at the end of the source file, and > is emptied before adding

Gedit haha.txt Open haha.txt file with Gedit Editor

More

More Test.txt If the contents of the Test.txt file are many, then display it in Split-screen mode

Ls-alh | More first put the contents of the LS-ALH display into the pipeline |, and then more from the pipeline to go to the data, and then split the screen display

mkdir: Creating a Folder

mkdir a creates a folder under the current path
mkdir a/b/c cannot be created,,, need to add-p

Tree: Displaying the folder structure as a directory tree

RmDir: Delete Empty folders

Rm:
RM haha.txt Delete a normal file
The RM folder will be prompted to delete something that is a folder,,, if really want to delete can add-r (recursively delete everything inside the folder)

Ln-s source File Link file means: Soft connection
The ln source file link file means: Hard link,, note that the number of hard links is 1 o'clock to actually delete the data, otherwise it will not

Cat 1. View the contents of a file
2. Merging multiple file needs and redirects > mates

Cat 1.txt 2.txt > 3.txt

grep: Search for required content from the specified file

-N: Show line numbers
-I: Case insensitive
-V: Inverse, that is, the row that does not contain the required content

Homework:
There is a file (content Custom), now you need to put all the content beginning with the letter A and the letter B end of all the content into a new file Result.txt

For example:
The source file is Test.txt and the contents are as follows:
sdfisdbbbb
Abcdefksjdfkjskdfksdj
akksjdfkjskdfj0000
Kjskdfjaaksjdfkjsdkfaaa
Ijijsdfjsdbbbbbb12
Bksjdkfjsdja
Kajsdkfjaksb
ksjdkfkasdbbbbb

The result after execution is:
Abcdefksjdfkjskdfksdj
akksjdfkjskdfj0000
sdfisdbbbb
Kajsdkfjaksb
ksjdkfkasdbbbbb

To find a file:
Find path-name ' *.t?t '

Wildcard characters, note points:
[A-za-z0-9]*.txt

To copy a file:
CP A B copies the A folder as a whole to the B folder
CP a/* B assigns all content under the A folder to the B folder

Cut files:
MV A B moves the A folder as a whole (cut) to the B folder

B----bytes
K----> Kbytes 1024B
M----> MBytes 1024K
G
T
P

TAR-CVF Xxx.tar * Packing
Gzip Xxx.tar Compression

Gzip-d xxx.tar.gz
TAR-XVF Xxx.tar

Common Compression Decompression methods:

TAR-ZCVF xxx.tar.gz *
TAR-ZXVF xxx.tar.gz

TAR-JCVF xxx.tar.bz2 *
TAR-JXVF xxx.tar.bz2

Linux: Multi-user multitasking OS

Ifconfig: View IP Address

Using ipconfig in Windows

Ping:

Ping 192.168.17.76 Test network connection is healthy

SSH: Telnet

SSH [email protected]
SSH User name @ip

WhoAmI: View Current user name

Who: View current logged in user information

Exit: Log Out

Useradd New user name-m-d/home/new user name-G group name

passwd User Name

The user name that SU needs to switch
Su-the user name that needs to be toggled, after switching the user, will also actively jump to the user's home directory

Python---->laowang----->python

sudo needs to be added when a super administrator is required, and at the front of the command line, spaces are required
sudo passwd Laowang

Sudo-s switch directly to the root user

Groupadd YYY Add a YYY user group
Groupdel YYY Delete a group,,, note that sudo is required

Cat/etc/group

Groups Laowang: View all user groups that Laowang belongs to

Usermod-g YYY Laowang Add the old king to the YYY group

Usermod-a-G xxx Laowang add Lao wang to XXX group

-G and-g,-g specify the default group

Useradd create a new user without sudo, or switch to root, need to add this user to ADM, sudo group inside can

chmod permissions to modify files

U: Owner
G: Same group
O: Others
A: all, i.e. U, G, O

+ Add Permissions
-Remove Permissions
= Set Permissions

R: Read------> corresponding number is 4
W: Write------> corresponding number is 2
x: Execution------> corresponding number is 1

chmod 777 folder, only modify the folder permissions to 777, will not modify the permissions of the file inside

-R modifies permissions for all files and folders within the folder (recursive)

Understanding: Mount Mount Commands

Vi
From command mode---Edit mode: I, A, O, I, A, O
----from edit mode command mode: ESC
From the command mode----the last line mode: Enter a colon, that is, shit+;

Last-line mode:
W Save
Q exit
！ Forced

Commonly used for:
Wq save exit, equivalent to X (lowercase x),,, also equivalent to shit+2 z in command mode
q! Do not save exit

Command mode:
HJKL control up and down function
M Middle Position
L The last line of the current screen
YY Copy, 8yy: Indicates copying 8 rows from the line where the current cursor is located
P Paste
DD Cut, 8DD: Cuts 8 lines from the line where the current cursor is located

U undo
Ctl+r Anti-Revocation

G to the last 1 lines
15G means jump to line 15th
1G means jump to line 1th

GG Jump To line 1th

Cloud disk information:http://pan.baidu.com/s/1jIR2ir0

"Linux Basics" linux basic command line learning notes