Emacs: Regular Expression
Regular Expression (aka regex) is a character sequence that represent a pattern for matching text. For example, you can use it to find all email addresses in a file by matching the email address pattern. Regex is used by many functions to check if a string contains certain pattern, or extract it, or replace it with other string.
(video tutorial: xah talk show 2022-08-04 emacs regular expression)
The most commonly used commands that use regex are:
list-matching-lines[see Emacs: List/Delete Matching Lines]
query-replace-regexp[see Emacs: Find Replace in Current File]
- Open a file with many lines.
It will list all lines that contains the regex pattern
th.t, which includes “this”, “that”.
. character in regex is a wildcard, matching any character.
Emacs Regular Expression
- Regular Expression
- About Quoting Regex
- Regex Syntax
- Case Sensitivity
- How to Insert a Tab or Newline
- Wildcards vs Regex