How to use regex in Notepad

To use regex in Notepad effectively, open the Replace dialog with Ctrl H, enter your pattern in "Find what", specify replacement text, and set Search Mode to Regular expression. 1. Use basic patterns like \d for digits, \s for whitespace, . for any character, ^ and $ for line boundaries, for one or more, for zero or more, and {n} for exact repeats. 2. Use capturing groups with ( ) and reference them with \1, \2, etc. 3. For practical tasks: remove empty lines with ^\s$ replaced by nothing; swap words like "Smith, John" using ^(\w ),\s (\w )$ and \2 \1; add prefixes like "Line: " by replacing ^ with the prefix; match multi-line content by enabling ". matches newline" and using START(.?)END. 4. Remember to escape special characters like ., , , ?, and others with \; test patterns with Find Next, back up files, and use case-insensitive search by unchecking Match case. While Notepad lacks advanced features like auto-numbering, its regex support is powerful for structured edits like log cleaning or code reformatting, and Ctrl Z can undo mistakes, making it a fast, reliable tool for text manipulation when used carefully.

Using regex (regular expressions) in Notepad is a powerful way to search and replace complex text patterns. Here’s how to use it effectively.

1. Open the Find and Replace Panel

Press Ctrl H to open the Replace dialog. This gives you access to both search and replace with regex.

• Find what: Enter your regex pattern here.
• Replace with: Enter the replacement text.
• Make sure Search Mode is set to Regular expression (and optionally check ". matches newline" if needed).

2. Basic Regex Syntax in Notepad

Notepad uses the Boost regex engine, so some syntax is slightly different from other tools.

Common Patterns:

• \d – Matches any digit (0–9)
• \s – Matches whitespace (spaces, tabs, newlines)
• \w – Matches word characters (letters, digits, underscore)
• . – Matches any character (except newline, unless enabled)
• ^ – Matches the start of a line
• $ – Matches the end of a line
• * – 0 or more of the preceding character
• – 1 or more of the preceding character
• ? – 0 or 1 of the preceding character
• {n} – Exactly n occurrences
• [abc] – Matches one of the characters inside the brackets
• ( ) – Capturing groups
• \1, \2, etc. – Backreferences to captured groups

Note: In Notepad , you don’t need to escape parentheses or curly braces in basic cases. But for quantifiers like {, use literal { unless it's part of a quantifier.

3. Practical Examples

Example 1: Remove empty lines

• Find what: ^\s*$
• Replace with: (leave empty)
• Check Wrap around and Regular expression
• Click Replace All

This matches lines with only whitespace (or nothing) and deletes them.

Example 2: Swap two words separated by a comma

Suppose you have:

Smith, John
Doe, Jane

And you want:

John Smith
Jane Doe

• Find what: ^(\w ),\s (\w )$
• Replace with: \2 \1

Captures last name and first name, then swaps them using backreferences.

Example 3: Add line numbers

You can’t auto-increment numbers directly, but you can prepend something:

• Find what: ^
• Replace with: Line:

  This adds "Line: " to the start of every line.

(For true numbering, you’d need a script or external tool.)

Example 4: Match multi-line text

Enable ". matches newline" to include line breaks in .

Example: Match everything between START and END across lines:

• Find what: START(.*?)END
• Replace with: REPLACEMENT
• Check ". matches newline"

4. Tips and Gotchas

• Case sensitivity: Uncheck Match case if you want case-insensitive search.
• Escape special characters: Use \ before ., *, , ?, (, ), [, ], {, }, $, ^, \, |.
• Use parentheses for groups: Then reference them with \1, \2, etc.
• Test first: Use Find Next to test your pattern before replacing all.
• Backup your file: Regex can make unintended changes.

Final Notes

Regex in Notepad is best for structured text editing—cleaning logs, reformatting code, or batch renaming variables. It’s not as full-featured as Python or Perl regex, but it’s fast and handy for text files.

Just remember: Ctrl Z is your friend if things go wrong.

Basically, write the pattern, test it, then replace. Not complex—but powerful when used right.

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