Linux Command Basics

Linux commands (provided by software written by developers)

An instruction or program used to implement a class of functions
The execution of the command depends on the interpreter program (for example:/bin/bash, etc.)

Ii. Classification of Linux commands

1. Internal Command (part of Shell interpreter): Comes with shell (for user and kernel interaction)
2. external Command (program independent of Shell interpreter): User-installed or released version comes with GNU software
3. Judging internal or external commands : type
Cases:
type cdDetermine the CD command type as internal command

type vimDetermine the VIM command type as an external command

Third, the format of the Linux command

        命令字  [ 选项 ]  参数

Detailed :
1. command word : specific use of commands
2. Options : The role of the specific adjustment command Word, short format-(simple, not easy to understand), long format-(easy to understand, not remember)
Example :
rm -rf-RF is a short format option, and multiple short format options can be written together
rm --force--force is long format option, multiple long format cannot be combined writing
3. parameters : Command Word Action object (to whom to use the command)

Four, Linux common shortcut keys

Tab: Auto-completing
Backslash "\": Force line break
Ctrl+u: Delete cursor to beginning of line
CTRL+K: Delete cursor to end of line
CTRL + A: Jump to the beginning
Ctrl+e: Jump to end of line
Ctrl+l or clear: Clear screen Content
CTRL + C: Interrupt current operation
Shift+pgup: Page Up
Shift+pgdown: Page Down

V. Linux commands to help get

internal Commands : Help < internal commands >//View the information about bash internal commands
External Command:< external command >--HELP//For most external commands
Man Handbook : Man < command >

1. Use the "↑", "↓" arrow keys to scroll the text
2. Page up with Page UP and PAGE DOWN keys
3. Press Q or Q to exit the reading environment, press the "/" key to find content; n jumps to the next find content, n jumps to the previous find
   Cases:
   helo echoInternal commands help get
   ls --helpExternal commands help get
   man ls 或 man echoGeneral Command Online manual access
   4. Save Man manual page: Man command Word | Col-b > saved file names
   "|" (pipe): The output of the preceding command as input to the following command
   "Col-b": Remove special characters
   ">" (Redirected Output): Save the output as a file
   Cases:
   man ls | col -b > ls_man.txtExport LS manual to ls_man.txt file; Col-b Remove special characters

Linux Command Basics