In a previous lesson, you learned that filename expansion symbols allow the Linux shell to expand filenames as arguments (referred to as “globbing”) for file management commands. This is very useful for managing multiple files sharing similar characteristics such as the same file extension. Used for Linux commands such as ls, rm, mv, cp, cat, less and more.

Regular expressions are used to search, edit and manipulate textand are used with Linux file management commands such as '''ls''', '''rm''', '''mv''', '''cp''', '''cat''', '''less''' and '''more'''. This can represent text contained in files or text as a result of issuing Linux commands using a pipeline.

A regular expression is A '''regular expression''' is a combination of two types of characters: '''literals ''' and '''special characters'''. In combination, these characters define a logical pattern. Strings of text can be compared to this pattern to see if they fit the pattern defined by the expression.