1.4 Special symbols in the shell

#命令输入特殊符号

* is match 0 or more characters

? is to match one character

#是加上这行不生效

\ is a de-righteous character

$ is the prefix of the variable, using the variable

; is used in the middle of two commands.

[] is matching two files

ls [12].txt = = ls 1.txt 2.txt

Exercises:

1. Which of the following special symbols is right?

LS *.txt will list all 1.txt 22.txt 333.txt.

Ls?. TXT will list all 1.txt 2.txt 3.txt

Touch \ #会创建一个文件名为 # files

2. What is the use of semicolons in the shell?

If you want to write multiple commands to a single line, you can add a semicolon between the commands

3. If there is 1.txt 2.txt 3.txt a.txt in the current directory, which files will be listed using the command LS [12].txt?

1.txt

2.txt

Summarize

Main: * is match 0 or more characters,? is a match for one character, [] is a match of two files

1.4 Special symbols in the shell