Wildcards are a set of building blocks that allow you to create a pattern defining a set of files or directories.
Here is the basic set of wildcards:
- * – represents zero or more characters
- ? – represents a single character
-  – represents a range of characters
Wildcards may be used with any command.
* in Linux
It represents zero or more characters. If you want to list all the files and directories then this wildcard is very beneficial.In simple words, whenever you use * means it will include all the character.
E.g. if you want to list all the directory which starts with D. Then you just have to write.
suppose you want to search all files with extension png.
? in Linux
it means list all the file whose first letter is an unknown but second character is o and i do not care about remaining characters in the file name.
it means I do not care about the file name. I care about extension only whose length consists of 3 characters.
 in Linux
It represents the range of characters. so, it is also called range operator.
i guess you got the basic understanding about wildcard.