2017-10-8linux basic Commands

One: basic commands

Login

User name: User ID

Authentication mechanism: Authentication authorization: Authorization Audit: Audition (log)

Command prompt prompt: Commands--Follow magic number: identifies binary format

#: Root$: Normal user

Kernel function: Process management memory management file system network function hardware-driven security mechanism

Virtual Switch Terminal: CTRL+ALT+F1-F7

Graphical user interface gui (Graphic user Interface): gnome:c kde:c++ XFace

Command Line Interface CLI: (Command lines Interface): SH bash csh ksh zsh tcsh

Switch users: SU (switch User)

# su [-l] User name

#exit//Return to the previous directory,

Change Password: passwd

Password Complexity rule: A uses at least 3 kinds of 4 kinds of characters wrongly written characters; b is long enough, greater than 7 bits; C uses random characters; d periodic replacement; E cycle period is large enough

DLL under Windows (Dynamic link library): Dynamically linked Libraries file ... Equivalent to. So (Shard object) under Linux

LS (list): List-r: Reverse Display-R: Recursive (Recursive) display

PWD (pringting working directory): Show current directory

CD (change directory): Switch directory

The CD does not add any parameters; go back to the user's home directory

CD ~username; Enter the user's home directory

CD-; switch back and forth between the current directory and the previous directory

Command type: Built-in command (shell built-in) when the system starts, it calls into memory, it is resident memory, so it performs high efficiency external command: The software function of the system, when the user needs to read into memory from the hard disk

Environment variables: named memory space printenv: Display environment variables

Type: display specifies which type to belong to

Get commands to use Help: internal command: "helper Command" external command: Command--help

Man command: View command user manual

Info COMMAND: online documentation

Document:/usr/share/doc

Man: Name: command name and function brief description

Synopsis: Usage notes, including available options

Decription: A detailed description of the command function, which may include the meaning of each option

Options: Explaining the meaning of each option

Files: The configuration file associated with this command

BUGS: report BUGS to e-mail address

**examples: Working with instances

See ALSO: Another reference

Turn screen: Turn back one screen: SPACE to turn one screen: B Turn back a line: Enter forward to turn a line: K

Find:/keyword: Backwards? KEYWORD: Forward N: Next N: previous Q exit

Whatis command: Shows the chapter in which the commands are

Man? Command man is divided into chapters: 1: User command (/bin,/usr/bin,/usr/local/bin) 2: System call 3: library file 4: Special file (device file) 5: File Format (configuration file Syntax) 6: Game 7: Miscellaneous (Miscellane ous) 8: Administration Command (/sbin,/usr/sbin,/usr/local/sbin)

<>: Required []: Optional ...: can appear multiple times |: Multiple selection One {}: Grouping

Date: View system time

Clock or Hwclock: View hardware time hwclock change hardware time

Cal: View Calendar

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2017-10-8linux basic Commands