Find & Replace

A regular expression is a pattern language for matching text based on rules rather than literal characters. For example, \d+ matches any sequence of digits, and [A-Z] matches any uppercase letter. In the Find field, enable regex mode and enter a pattern. Common patterns: . (any character), * (zero or more), + (one or more), ^ (start of line), $ (end of line).

With whole-word matching enabled, the search only matches the search term when it appears as a complete word — surrounded by spaces, punctuation, or line boundaries. For example, searching for 'cat' with whole-word on will match 'cat' but not 'catch' or 'concatenate'. This prevents partial-word replacements.

Case-sensitive matching distinguishes between uppercase and lowercase letters, so 'Hello' and 'hello' are treated as different strings. With case-insensitive matching, both are treated as equal matches. Case-insensitive mode is useful when you want to replace all variants of a word regardless of how it was capitalized.

Yes. In regex mode, you can reference captured groups in the replacement using $1, $2, etc. For example, if your pattern is (\w+)\s+(\w+) (matching two words), a replacement of $2 $1 would swap them. This enables powerful text restructuring beyond simple substitution.

The tool processes text in your browser with no server restrictions. Very large texts (megabytes) may slow down due to browser memory and JavaScript processing time, particularly with complex regex patterns applied to many matches. For typical documents and code files, processing is nearly instantaneous.