Linux Learning Essay Three

First, the root directory detailed

Second, the file command uses

ls/ Enter the root directory

/ boot system startup related files

such as kernel, INITRD, and Grub (bootloader) boot loader

/ dev device files

Light blue link File, * * * for special files

The device files are:

Block devices: Random access, data blocks

Character Devices: Linear access, by character

Device number: Main device number (major) and secondary device number (minor)

/ etc configuration file

/home User House Directory

Each user's home directory usually defaults to/home/username form

/root Administrator home directory (in production environment is not recommended to log in root, the permissions are too large, easy to make mistakes, need to use permissions and then login)

/lib Library files cannot be used alone and can only be called

/lib/modules kernel module files

The library file has a static library. A

Dynamic Library. dll. So (Shared object)

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File libc-2.5.so

File/bin/ls

With two commands you can see that running LS needs to call libc This file, it is also a shareable file

/media mount point directory, typically a mobile device

/mnt mount point directory, usually additional temporary file system mounts

/opt Optional Directory

/proc pseudo file system, kernel mapping file

/sys Pseudo file system, property mapping files related to hardware devices

/ tmp temp file/var/tmp is also a temporary file

/ var changeable files

/bin executable file, user command

/sbin Management commands

/usr shared,read-only

/usr/bin

/usr/sbin

/usr/lib

/usr/local

/usr/local/bin

/usr/local/sbin

/usr/local/lib

Not all of the above local is necessary.

File naming rules

1, the length can not exceed 255 characters

2. Cannot use/when file name

3. Strictly case-sensitive

Directory Management Commands:

LS CD pwd

Mkdir
English Intent: Make directories
Location:/bin/mkdir
Execute Permissions: All Users
Syntax: mkdir-p "directory Name"
Function Description: Create a new directory
Option-P Recursive creation

-V details (verbose)

Example: MkDir A

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Mkdir-p/tmp/123/456

Tree view Directory Trees

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Mnt/test/x/m,y mnt under Create test and underneath the x,x contains m,test under Create Y, how to execute once

mkdir-pv/mnt/test/x/m mnt/test/y

Mkdir-pv/mnt/test/{x/m,y} curly braces indicate command line expansion, and this can also be expanded

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How to create a Mnt/test2/a_b,a_c,d_b,d_c

(a+d) (b+c) =AB+AC+DB+DC

{A,d}_{b,c}

MKDIR/MNT/TEST2/{A,D}_{B,C}

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RmDir Delete directory (remove directory), note that only empty directories can be deleted

Rmdir-p/mnt/test2/a_c

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Creation and deletion of files:

#touch can create a file, but its main function is to modify the timestamp

Location:/bin/touch
Execute Permissions: All Users
Syntax: Touch "file name"
Function Description: Create an empty file

Touch a

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Stat a650) this.width=650; "src=" Http://s3.51cto.com/wyfs02/M01/74/91/wKiom1Yg6dihiFO5AAH6KIoMtgM873.jpg "title=" Qq20151016201257.png "alt=" Wkiom1yg6dihifo5aah6kiomtgm873.jpg "/>

touch-c C does not create a file

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Touch-a a change the file access time

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touch-m A change the file modification time

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TOUCH-MT 201212121212 A Specifies the file modification time

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Access time, modify modify time, change state time

ASCII American Information Interchange Code

Stat is three times to view files

RM Delete file (too much permission, use sparingly)

Options:

-F: Force delete

-r: Recursively delete directory

RM-RF/This named caution operation, is to delete the root directory, destroy the system's move, deadly operation

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Linux Learning Essay Three