Linux_ file system and document management basics

File system:
Rootfs: Root file system

Fhs:linux

/boot: System boot related files, such as kernel, INITRD, and Grub (bootloader)
/dev: Device files
Device files:
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 directory for users, the home directory of each user is usually the default of/home/username
/root: Administrator's home directory
/lib: library file
Static Library,. A
Dynamic library,. dll,.so (Shared object)
/lib/modules: Kernel module files
/media: mount point directory, usually mounted on a mobile device
/MNT: Mount additional temporary file system
/OPT: Optional directory for early installation of third-party software
/proc: Pseudo file system, kernel mapping file
/sys: Pseudo file system, property mapping file related to hardware device
/tmp: Temp file,/var/tmp
/var: a variable file
/bin: Executable file, user command
/sbin: Managing Commands

/usr: Shared read-only files globally
/usr/bin
/usr/sbin
/usr/lib

/usr/local:
/usr/local/bin
/usr/local/sbin
/usr/local/lib


File naming rules:
1, the length can not exceed 255 characters
2. Cannot use "/" as file name
3. Strictly case-sensitive


Directory Management:
Ls
Cd
Pwd
Tree: Viewing the directory tree

mkdir: Creating an empty Directory
-P: Recursive creation
-V: Show more information

RmDir: Delete Empty directory
-P: Recursive delete empty directory, single branch
-V:

List:ls
Lists, lists the files under the specified path
-L: Long format displays full information
File type: the
-: Normal file (f)
D: Catalog file
B: Block device files (blocks)
C: Character device file (character)
L: Symbolic Link files (symbolic link file)
P: Command pipe file (pipe)
S: Socket file (socket)

File permissions: 9-bit, every 3-bit group, each group: rwx (Read, write, execute), r--

Number of hard links to files

Owner of the file

Genus Group of files

File size (size), default unit is byte

Timestamp (timestamp): Last Modified Time
Access: Access
Modified: Modify, the file content has changed
Change: change,metadata, meta data
-H: Unit conversion
-A: Show hidden files starting with.
. Represents the current directory
.. Indicates a parent directory
-A:
-D: Display the directory's own properties
-i:index Node,inode (Index node)
-r:desc sort
-R: Recursive (Recursive) display

Cd:change Directory
CD ~username: Enter the user's home directory
CD-: Switch back and forth between the current directory and the previous directory


File Management:
File: Show Files Type
Stat: View the detailed status of a file
Touch: Create an empty file
-A: Change access time only
-M: Change only the modified file
-T: Specify timestamp [[CC]YY]MMDDHHMM[.SS]
-C: Do not create a new file when the file does not exist

Create a file using the file editor
Nano
Vi
Vim

To delete a file:
Rm:
-R: Recursive delete
-F: Do not prompt for immediate deletion
-I: interactive Delete, hint

Copy file: (Cp,install)
cp:copy, copy a file to a file, copy multiple files to a directory
CP Source_file Destination_file
-R: Recursive replication for copying files in directories and directories
-F: Forcibly copied, overwritten, without prompting
-I: Interactive
-P: Preserve the source file permissions, owner, timestamp
-A: Archive, often used for backup
-L: If the source file is a linked file, copy the linked source file
-P: Copy a linked file instead of a linked source file


Mv:move Moving files
MV Source_file Destination_file

Install-d directory ...: Creating directories


Find the file name:
Whereis [-BMSU] filename
-B: Find only binary files
-M: Find only in the description file path manual
-S: Find source files only
-U: Find other special files that are not among the above three options

To find a file using find:
Find [PATH] [option] [action]
Find/-mtime 0: Finding files within the current time to 24 hours
+ 4: Find files greater than or equal to 5 days ago
-4: Find files in less than or equal to 4 days
4: Find files between 4-5 days

Find/home-user Root--Find all files from the root user in the/home directory
-nouser

-name filename--Find a file named filename
-size [+-]size--Find files larger or smaller than size (-size +50k)
-type Type--Find a file of type file

-perm mode--Find files equal to mode
-perm +mode--Find the file that must contain all mode, greater than mode
-perm-mode--Find a file that contains any mode

Text Management:
To view text:
Cat
-N: Show line numbers
-e: Show Line endings
TAC:CAT reverse Order

MORE: Turn backwards
Less
/String down query string
? string up query string, less available
Space PAGE Down
b PAGE Up

Head
Head-n filename View file header 20 lines
Head-n -100 filename does not show the last 100 rows

Tail
Tail-n filename View file trailing 20 lines
Tail-n +100 filename does not show header 100 rows

-F: Look at the end of the file, do not exit, wait to display new content appended to this file


Text Processing:
Cut
-D: Specify delimiter, default is space
-F: Specify the fields to display
-f1,3: Show 1th, section 22 fields
-f1-3: Show 1th to 33rd fields
Text sort:
Sort: Default ASC sort
-N: Sort by value
-r:desc
-T: Specify delimiter
-K: Which field is the sorting criterion
-U: Remove duplicate items, show only once
-F: Ignore case
[Email protected] ~]# sort-t:-k3-nr/etc/passwd

Uniq
-C: Shows the number of rows in a file that repeats
-D: Show only duplicate rows

Text statistics:
Wc:word Count
-L: Show only the number of rows
-W: Displays only the number of words
-C: Show only the number of bytes
-M: Displays only the number of characters
-L: The longest line contains the number of characters

Character Processing:
TR: Used to convert or delete characters
TR [OPTION] ... SET1 [SET2]
[[email protected] ~]# echo "AAAAHSDF" |tr ' A-Z ' A-Z '
Aaaahsdf
-D: Delete characters
[[email protected] ~]# echo "AAAAHSDF" |tr ' a '-D
----HSDF

Linux_ file system and document management basics