Linux commands basic

1.ls: List Folder directory

-A lists all files (including hidden files)

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- L list files and folders for more information

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More information:

1) The meaning of the first number of digits in the front

-: Normal file

D: Catalog file

B: Block device files

C: Character device file

L: Link Device files

P: Command Pipeline file

S: Socket file

2) The following 9 digits are the permissions for the file or folder, and 3 are a set of

R: Read permissions

W: Write permission

X: Executable Permissions

The first three are the permissions of the current host, the permissions of the middle three genera, and the last three permissions for the other users

3) The number after the permission is the number of times the file or folder has been linked

4) The first root represents the current file owner, the second root represents the group of the current file

5) Size of the file or folder (in bytes),-H: can be converted to size units

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6) Date the file was created

7) Name of the file or folder

2. Man Command: User manual for this command (manual)

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Meaning of the symbol:

< > must give the content; [] Optional content

... Can be used more than once; {} group

Man: There are a few commonly seen

Name: command names, brief description

Synopsis: Usage Notes

Description: Detailed description

Options: Explaining the meaning of each option

Examples: Using the example

File: The configuration file associated with this command

Instructions for using man:

Flip Screen:

Front Turn (b) turn backward (space) by one line (Enter) and turn forward (k)

Find:

(/keyword) in the past to look for (? Keyword) looking forward (n) the next (n) Previous

Exit: Q

3.whatis command: You can see the chapter that the command appears

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(1) User command (/bin/,/usr/bin,/usr/local/bin)

(2) System call

(3) Library call

(4) Special documents (equipment files)

(5) file format (configuration file syntax)

(6) Games

(7) Miscellaneous

(8) Management order (/sbin,/usr/sbin,/usr/local/sbin)

4, Linux has two clocks, one is the hardware clock (Real time Clok, referred to as RTC), and the other is the system clock

hwclock/clock: Hardware time

Set Hardware time:

Hwclock--set--date= "03/03/13 10:56" (Month/day/year: minutes: seconds)

Clock--set--date= "03/03/13 10:56" (Month/day/year: minutes: seconds)

Date: System time

Date--set "03/03/13 10:56" (Month/day/year: minutes: seconds)

Sync Time:

Hardware time and System time synchronization: HWCLOCCK--hctosys/clock--hctosys

System time and Hardware time synchronization: Hwclock--systohc/clock--SYSTOHC

5.cal: Calendar

Usage: cal [Options] [[[Day] month] year]

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6, online documentation;

Info Command: A detailed description of the origin of the command

7,Echo "": Output character

-E: color can be displayed

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8. File: View files Type

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Linux commands basic