hugo/content/en/_common/functions/regular-expressions.md

---
_comment: Do not remove front matter.
---

When specifying the regular expression, use a raw [string literal] (backticks) instead of an interpreted string literal (double quotes) to simplify the syntax. With an interpreted string literal you must escape backslashes.

Go's regular expression package implements the [RE2 syntax]. The RE2 syntax is a subset of that accepted by [PCRE], roughly speaking, and with various [caveats]. Note that the RE2 `\C` escape sequence is not supported.

[caveats]: https://swtch.com/~rsc/regexp/regexp3.html#caveats
[PCRE]: https://www.pcre.org/
[RE2 syntax]: https://github.com/google/re2/wiki/Syntax/
[string literal]: https://go.dev/ref/spec#String_literals
Squashed 'docs/' content from commit 5c085a37b git-subtree-dir: docs git-subtree-split: 5c085a37b297bf12f59efeaae591418ec025c10d 2024-01-27 10:48:33 +01:00			`---`
Squashed 'docs/' changes from 227aab619..8390a4a3a 8390a4a3a Add Void Linux installation instructions d6099aae8 Update link to PostCSS plugins 25dad4693 netlify: Hugo 0.139.4 2b1fa118c Fix typo 3ef1eb505 Update hosting-on-aws-amplify c0f6d35d6 Fix typo aa54d4301 Correct directory name 98aa26bdb Improve instructions for hosting with AWS Amplify a07638a80 Add new-in badges 6ad018055 netlify: Hugo 0.139.3 1050835d6 Update title of hugo.Store page ebbd2e851 Clarify the shortcode Ordinal method b7716ed95 Revise code block render hook for Mermaid diagrams f1da9b6ea netlify: Hugo 0.139.2 d8ac9f428 Downgrade the Go toolchain in go.mod to a slightly older Go version 254b3c4f2 netlify: Hugo 0.139.1 03e666038 Add hugo.Store, site.Store and Shortcode.Store 157e8983b Update Anchorize.md 59fa9f214 Document the PageRef menu entry method bda544cce docs(transform.Unmarshal): match lang attribute to title language in examples 1985886bd Adjust front matter of shared Markdown snippets da5bd70d1 Fix typo 431b65d6b Update theme b63ef69f5 Update style guidance d50ed3422 Remove old new-in badges 12bfb9933 Update docs.yaml 0b936cacd netlify: Hugo 0.139.0 ab7668b4d dartsass: Add silenceDeprecations option 154df9bfc Merge commit '838bd312b1a287bb33962ad478dbc54737654f35' efa80477c docs: Regen CLI docs ad99e4a7a docs: Regenerate CLI docs git-subtree-dir: docs git-subtree-split: 8390a4a3ac36094f4cf47170af23b636608c420e 2024-12-11 09:53:33 +01:00			`_comment: Do not remove front matter.`
Squashed 'docs/' content from commit 5c085a37b git-subtree-dir: docs git-subtree-split: 5c085a37b297bf12f59efeaae591418ec025c10d 2024-01-27 10:48:33 +01:00			`---`

			`When specifying the regular expression, use a raw [string literal] (backticks) instead of an interpreted string literal (double quotes) to simplify the syntax. With an interpreted string literal you must escape backslashes.`

			Go's regular expression package implements the [RE2 syntax]. The RE2 syntax is a subset of that accepted by [PCRE], roughly speaking, and with various [caveats]. Note that the RE2 `\C` escape sequence is not supported.

			`[caveats]: https://swtch.com/~rsc/regexp/regexp3.html#caveats`
			`[PCRE]: https://www.pcre.org/`
			`[RE2 syntax]: https://github.com/google/re2/wiki/Syntax/`
			`[string literal]: https://go.dev/ref/spec#String_literals`