Linux Basic Learning -10.1-Special symbols-category explanation

1. REDIRECT Symbol

01, > Output redirection first empty the file, append

02, >> Append output redirect Append

03. < input redirection and Xargs TR

04. << Additional Input redirection

Cat appends multiple lines to a file.

Cat >>/oldboy/alex.txt<<eof

Love Me, Love my dog.

Love Li, Love li ' s dog.

Eof

2, the position of the

01,. (point) Current directory

02,.. Current directory Top level directory

03, ~ Current user's home directory

3. Special symbols

01. # Note The root user's command prompt

02. The contents of the variable (command line) take a column (awk) a command prompt for a normal user

03,! Find the most recently used command and then perform find exclude/Take back awk to remove vim enforcement

History \|grep awk

04, | Pipeline

; Split multiple commands.

4. Quotation mark Series

01, "$ ()

02, "What you see is what you get, show it intact."

03, "" Analysis of special symbols

5. Simple Judgment

01, && Previous command executed successfully, execute the following command

Ifdown eth0 && ifup eth0

02, | | Previous command execution failed, execution of subsequent command

Ls/alex \|\| The echo directory does not exist

Exercises:

All the special symbols and meanings of dictation

Linux Basic Learning -10.1-Special symbols-category explanation