regex that all matches blank line

A regular expression that matches blank lines (lines that contain only whitespace or are completely empty) is:

^\s*$

Explanation:

• ^ → Matches the beginning of the line.
• \s* → Matches zero or more whitespace characters (spaces, tabs, etc.).
• $ → Matches the end of the line.

This regex ensures that lines that contain only whitespace (or nothing at all) are matched.