Regular Expressions

Imagine, rather than typing all the file names, you could represent them with a single word. This word or a pattern used to represent files/directories are called regular expression (regex for short).

• Simple examples:
• to represent any word: eg. *.txt means all files with txt extension
• ? to represent a single letter: eg. ?????.txt matches all files with exactly 5 letters, with txt extension.
• ^ beginning and $ for the end of the word: eg ^text* forces the match for the beginning letters only.