Shulou(Shulou.com)06/02 Report--

# basic Linux commands

Classic quotations of Linux system:

After the command operation, there is no message, which is the best news.

The system starts from the root.

Everything in the system is a file.

I. Linux system command structure

Command + space + condition / parameter + space + object / directory / file

For example: rm-f / oldboy

Two. Shutdown or restart command

Shutdown command

[- r] restart

[- h] shutdown

[- c] cancel shutdown / restart

[- t] automatically after a certain period of time

For example:

Shutdown-r restarts in a minute.

Shutdown-h shuts down the system in a minute.

Reboot / shutdown in 10 minutes after shutdown-RRAMUBER

Shutdown-Randall Murh now now restart / shut down immediately

Generally, the default unit is minutes.

Halt

-n: do not write the memory data back to the hard disk before shutting down

-W: it doesn't really turn off, just write the record in / var/log/wtmp file.

-d: do not write records to / var/log/wtmp file (- n parameter contains-d)

-f: forced shutdown, do not call the command shutdown

-I: stop all network-related devices before shutting down

-p: turn off the power supply (poweroff) by the way when you turn it off

For example:

Halt shuts down the system

Halt-p shut down the system and power off

Halt-d shuts down the system without leaving a record

InIt

0: shutdown

1: single-user mode, only root is used for maintenance

2: multi-user, no network

3: completely multi-user

4: multi-user-unused

5: graphical

6: the restart usage is simple.

three。 Switch directories

Cd-

Cd-switch directories cd.. -return to the previous directory cd.. /.. /-return to the previous two and directories cd ~ / cd-- return to the home directory cd-return to the last directory such as: cd /-switch to / (root directory) cd / oldboy-cut Change to the oldboy directory under / (root directory)

four。 Create a directory / file

Mkdir (create directory)

For example: mkdir / oldboy-create an oldboy directory under the root directory

Mkdir-p-create a multilevel directory

Mkdir-v-displays directory creation prompts

Mkdir-m-set directory permissions when creating a directory

Touch (create or update files)

For example

[root@yu yuxi] # touch 123

[root@yu yuxi] # ll

Total 0

-rw-r--r--. 1 root root 0 Oct 21 19:18 123

[root@yu yuxi] # touch 123

[root@yu yuxi] # ll

Total 0

-rw-r--r--. 1 root root 0 Oct 21 19:19 123

five。 View directories / files

Ls View Catalog

Ls-list showing data information

Ls-d-only check whether the specified directory exists

Ls-l-View detailed attribute information of the data

Ls-a-View all file information (including hidden files)

Ls-t-View data information sorted by time

Ls-r-View data information in reverse order

Ls-S-View data information sorted by size

Ls-F-check the directory information will be followed by / tag

Cat View Files

Cat-View file information

-n-view file line number information

Less (read the document as you read, enter ↓ / ↑ up, press the page space ↓ / b ↑)

More (read as if you read the document enter by line ↓ / up shift+ ↑ press page space ↓ / b ↑)

six。 Edit a file

1.vi-Editing file information

Basic usage

01 enter I and start editing

02 Press esc after content editing is finished

03: W-quit editing

PS:% s#oldboy#oldgirl#g-replace the specified information in the file

Echo-output information to the screen

Echo "hello world" > / oldboy/oldboy.txt

First empty the contents of the file and edit the contents of the file

Echo "I love you" > > / oldboy/oldboy.txt

Append the edited content to the end of the file content

seven。 Check the network

Ping-check if the network link is open

View URL address information

Ip address show eth0-View the address information of the eth0 network card

Abbreviation:

Ip a s eth0

Ip a

Test the corresponding port of the server

Telnet-Test whether the corresponding port of the server is accessible

Telnet host IP address port number

eight。 Delete directory / file

Rm- delete data information

Rm-f delete file information

Rm-rf delete directory information

Rm-rf /. * Delete everything in the root directory (bloody try not to try)

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