Basics of Linux Learning commands

Absolute path: Starting from the root
Relative path: Not the path from the root (discussed relative to the current path)

Ls:

[Email protected] ~]# ls-ltotal 190316-rw-r--r--1 root root 0 Jul 4 1-rw-r--r--1 root root 8 June 2 1.txt-: View file details

-L: View file details

File type
-: Normal file
D: Catalog file
B: Block device files (blocks)
C: Character device file (character) ls-l/dev
L: Symbolic Link files (symbolic link file)
P: Command pipe (pipe)
S: Socket file (SOCKET) LS-L/tmp
File permissions: 9-bit, per 3-bit group, per group: rwx (Read, write, execute)
Number of hard links to files
File owner
Filegroup (Group)
File size (size): Default bytes per unit
Timestamp (timestamp): Last Modified Time
Time Stamp Type
Access: Access
Modified: Modify file content changed
Change: Change file metadata, modify properties such as modify filename
-H: Unit conversion
-A: Show all files, including hidden files
Already "." Start file as hidden file
The default is "." In the directory. ".." Directory, "." For current directory "..." Parent directory of the current directory
-A: Do not show "." ".." Directory
-D: Display the directory's own properties
-i:index Node,inode Miniature Node number
-R: Reverse display is displayed by default in ascending order
-R: Cabinet display displays current directory and subdirectories all files (memory consumption)

cd:change Directory switch Directories
Without parameters: Go to the user's home directory
~: Go to home directory
~username: Enter the specified user home directory
-: Switch back and forth between the current directory and the previous directory

Command type
Built-in command shell built-in commands
External command: There is an executable file corresponding to the command name in a path on the file system
Type : Shows which type the specified command belongs to
Environment variables: named memory space
Variable assignment We don't have to take the command path when we knock the command.
printenv: Display environment variables
Path: Follow the path path to find the command path using ":" To separate the first directory under which to find the command, will take precedence to use this directory command
command will be cached after use, hash can be viewed

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Basics of Linux Learning commands