How to Replace Text in Notepad++ Using Wildcards (Regular Expressions)

To replace text using wildcards in Notepad++, you need to enable the "Regular Expression" search mode within the Replace dialog box and utilize specific regular expression syntax for pattern matching. This powerful feature allows you to match complex patterns, not just exact strings.

Essential Steps for Wildcard Replacement

Here’s a step-by-step guide to performing replacements with wildcards (regular expressions) in Notepad++:

Open the Replace Dialog:
- Press Ctrl + H on your keyboard, or go to Search > Replace.... Alternatively, you can press Ctrl + F and then switch to the "Replace" tab.
Enable Regular Expressions:
- In the bottom-left corner of the Replace dialog box, locate and tick the "Regular expression" radio button. This is crucial for Notepad++ to interpret your search pattern as a wildcard expression rather than a literal string.
Enter Your Search Pattern:
- In the "Find what:" field, type the regular expression that defines the pattern you want to find. For a basic wildcard that matches any sequence of characters, you would use .*.
Enter Your Replacement Text:
- In the "Replace with:" field, enter the text you want to use as a replacement. This can include static text or even parts of your matched pattern using backreferences (explained below).
Execute the Replacement:
- Click "Replace" to replace the next occurrence, "Replace All" to replace all occurrences, or "Find Next" to preview matches before replacing.

Understanding the `.*` Wildcard

The .* sequence is a fundamental regular expression wildcard in Notepad++:

. (dot): Matches any single character, except for a newline character (\n) by default.
* (asterisk): This is a quantifier that means "zero or more occurrences" of the preceding element.

When combined, .* effectively matches any sequence of characters (including an empty sequence) on a single line. If you need to match across multiple lines, you might need to enable the . matches newline option within the Replace dialog, depending on your Notepad++ version and specific requirements.

Common Regular Expression Wildcards and Metacharacters

Regular expressions offer a rich set of wildcards and special characters (metacharacters) for sophisticated pattern matching. Here are some of the most frequently used ones:

Basic Wildcards & Quantifiers

.: Matches any single character (except newline).
*: Matches the preceding character or group zero or more times.
+: Matches the preceding character or group one or more times.
?: Matches the preceding character or group zero or one time (makes it optional).
{n}: Matches the preceding character exactly n times.
{n,}: Matches the preceding character n or more times.
{n,m}: Matches the preceding character between n and m times.

Character Classes

\d: Matches any digit (0-9).
\D: Matches any non-digit.
\w: Matches any "word" character (alphanumeric and underscore, [a-zA-Z0-9_]).
\W: Matches any non-word character.
\s: Matches any whitespace character (spaces, tabs, newlines, etc.).
\S: Matches any non-whitespace character.
[abc]: Matches a single character that is 'a', 'b', or 'c'.
[a-z]: Matches any lowercase letter.
[^abc]: Matches any single character that is NOT 'a', 'b', or 'c'.

Anchors

^: Matches the beginning of a line.
$: Matches the end of a line.
\b: Matches a word boundary.
\B: Matches a non-word boundary.

Grouping and Backreferences

( ): Groups characters into a sub-expression and "captures" the matched text.
\1, \2, etc.: In the "Replace with" field, these refer to the text captured by the first, second, or subsequent grouping parentheses in your "Find what" expression.

Practical Examples of Wildcard Replacement

Let's illustrate with some common scenarios:

Scenario	Find what (Regex)	Replace with	Description
Removing text between two markers	`START_TAG.*?END_TAG`	`REPLACEMENT_TEXT`	Replaces text between `START_TAG` and `END_TAG` (non-greedily `?`) with `REPLACEMENT_TEXT`.
Extracting and reordering data	`(\d{4})-(\d{2})-(\d{2})`	`Year:\1 Month:\2 Day:\3`	Finds a date in YYYY-MM-DD format and reorders it using captured groups. `\1` refers to the first `()`, `\2` to the second, etc.
Deleting lines starting with a specific prefix	`^DELETE THIS.*$\R?`		Finds lines beginning with "DELETE THIS" and all characters until the end of the line, then deletes the entire line (including newline).
Replacing specific words at line start	`^old_word`	`new_word`	Replaces `old_word` only if it appears at the very beginning of a line.
Changing all numbers to placeholders	`\d+`	`[NUMBER]`	Finds one or more digits and replaces them with the string `[NUMBER]`.
Fixing inconsistent spacing	`\s{2,}`	` `	Replaces two or more consecutive whitespace characters with a single space.

Additional Tips for Effective Regular Expression Usage

Test Your Regex: Before performing a "Replace All," always use "Find Next" to ensure your regular expression is matching exactly what you intend.
Case Sensitivity: Notepad++'s Replace dialog includes a "Match case" checkbox. Tick it if your search needs to be case-sensitive, or leave it unticked for case-insensitive matching.
Consult Resources: Regular expressions can be complex. For advanced patterns, refer to reputable online regex testers or guides like Regular-Expressions.info or regex101.com.

By mastering these steps and understanding the common regular expression wildcards, you can perform highly efficient and precise text replacements in Notepad++.