Basic principles of Linux

1, by the purpose of a single small program composition: The combination of small procedures to complete complex tasks;

2. All documents:

3, try to avoid capturing the user interface: Do not interact with the user,

4, the configuration file is saved in plain text format;

GUI Interface:

CLI interface: Input command

Command prompt, prompt indicates that a command can be entered; Bash (shell)

#:root

$: Normal User

Command: command will be sent to the kernel

Command format: usually consists of three parts

Command option Parameters

Options: Modify how commands are executed,

Short options:-Letters

Multiple options can be combined:-a-b =-ab

Long options:--

Usually cannot be combined

Parameters: The Action object of the command

To use the voucher:

The user is the logo we use, or use the voucher.

Virtual Terminal (terminal): Multiple terminals (CTRL+ALT+F1-F6)

Graphic Terminal (CTRL+ALT+F7)

There are three graphic terminals: GUI

Gnome:c

Kde:c++

XFace:

Cli

Sh

Bash

Csh

Zsh

Ksh

Tcsh

Switch users

Su:switch User

#su-L user name to switch users (-l switch completely, not add, half switch)

Change Password

#passwd the back and then connect the password two times

Password complexity rules:

1. Use at least 3 kinds of 4 kinds of characters wrongly written characters

2, long enough, greater than 7 bits

3. Using Random strings

4, regular replacement;

5, the cycle period is large enough;