regex with special characters code example

Example 1: regex match numbers and special characters

echo %H1E2L+L#O! | sed 's/[^A-Z!]//g'	#replaces number and special
characters which aren't ! or an uppercase letter A-Z

Example 2: regular expression escape character

regex = / a/; // match a bell or alarm
regex = / e/; // matches an escape
regex = / f/; // matches a form feed
regex = / n/; // matches a new line
regex = / Q…E/; // ingnores any special meanings in what is being matched
regex = / r/; // matches a carriage return
regex = / v/; // matches a vertical tab