Shell Special Symbols

Symbol	Meaning
;	Command delimiter
#	configuration file comments; Root user command terminal prompt
~	Home Directory CD ~
-	Previous Path CD- Su-linux Switching user Environments
^	Non-[^ABCD]
$	Variable before adding $ out of variable contents
‘‘	Output AS-is
""	$  ``  ! These symbols can be parsed and other characters are output as-is
!	No, take the reverse [!ABCD] Command executes a command that was executed before !+ commands for numbers in the history
``	Used to reference a command equivalent to $ ()
{}	Content sequence {A,c,h} represents a C h {A.. Z} indicates a to Z Command block combination (module) In Linux regular, the number of repetitions {3,5} represents 3 to 5 times echo {1..10..2} 1 3 5) 7 9 echo {A.. Z.. 2} A c e g i k m o q s u w y
()	Character sequence grouping
||	Or the previous command failed to execute the following command
|	Pipe;
&&	The following command is executed only if the previous command is executed successfully
&	Command background Run
.	The current directory, the beginning of a hidden file name in Linux, any character in a regular expression; loading a file content
..	Parent directory; {A.. Z
/	Root or Path delimiter
\	Placed in front of the command keyword in Linux to block system aliases; escape

*	Represents any number of arbitrary characters; in Linux regular, repeat the previous character any time
?	Represents any one character; in Linux regular, repeat the previous character 0 or 1 times
+	Repeat the previous character 1 or more times
[]	Also means "there must be a character in parentheses" (not any character). For example [ABCD] represents "must have a character, may be a, B, C, d these four any one"
[-]	If a minus sign is inside the brackets, it represents "all characters in the code order." For example [0-9] represents all numbers between 0 and 9, because the language encoding of the numbers is continuous!
[^]	If the first character in the brackets is an exponential sign (^), that means "invert selection", for example [^ABC] means that there must be a character, as long as the non-A, non-B, not the other characters of C will accept the meaning.

Shell Special Symbols