Special symbols in the shell

* As a wildcard character, you can represent multiple characters, such as *.txt
? wildcard character, which represents only one such as. TXT a.txt
# in the shell script, #放在行首, the bank does not take effect
\ Caret, \ Revert special characters to normal characters
| Pipe break throws the command result before the symbol to the command following the symbol
$ as the identifier before the variable

! $ represents the last variable of the previous command
often used in the middle of two commands
~ User's home directory
& can put a command in the background, for example: Sleep &
[] The middle is a combination of characters, such as [12] means not 1 is 2
[1-9] [A-z] denotes a range

Special symbols in the shell