THE FEUTEX TOOLKIT

Bash Regex Snippet Builder with JavaScript Preview

JS match/replace preview; Bash/grep snippets; shell quoting; ERE incompatibility warnings. Previews matches with JavaScript regular expressions and generates shell snippets. The preview does not execute Bash or grep regex engines.

Scope of this tool: Previews matches with JavaScript regular expressions and generates shell snippets. The preview does not execute Bash or grep regex engines.

Mode

This tool runs locally in your browser. Matching is done with the browser regex engine; results are closest to the selected mode, but edge cases may differ from your exact Bash/grep build.

Flags (JS-style)

Common: g (all matches), i (ignore case), m (multiline), s (dotall). For Bash mode, m/s don’t map 1:1.

Regex

Replacement (optional)

Input text

Tip: paste multiple lines; use flag m if you want ^/$ to act per-line (JS behavior).

Output

Hash Tool Windows 10 — SHA-256 / SHA-1 / SHA-384 / SHA-512 / MD5

Hash Tool Windows — SHA-256 / SHA-1 / SHA-384 / SHA-512

JSON Tools for Notepad++ — Format, Minify, Validate, Sort Keys

Lenovo UUID Tool (SMBIOS ↔ UUID Converter + Validator)

Free File Hash Tool (SHA-1 / SHA-256 / SHA-384 / SHA-512)

Bash note: In real Bash, quoting changes behavior. For [[ $s =~ regex ]], don’t put the regex in quotes unless you want a literal string match.

Privacy: review the processing notes for this tool. Advertising makes separate network requests; see the Privacy page.

How to use

Quick workflow:

Select Mode (Bash [[ =~ ]] or grep -E).
Enter a Regex and your Input text.
Click Test to list matches and groups (add flag g to list all).
Optionally enter a Replacement and click Replace.
Use Generate snippet to copy a Bash/grep example.

FAQ

Is this an exact Bash [[ =~ ]] engine?

No—matching runs with your browser’s regex engine; the tool focuses on fast debugging and snippet generation, with warnings where Bash/ERE commonly differs.

Why does my Bash regex fail when I put it in quotes?

In [[ $s =~ regex ]], quoting the regex turns it into a literal string comparison; generally leave the regex unquoted.

Does grep -E support \d or \w?

No; POSIX ERE uses character classes like [0-9], [[:alpha:]], and [[:alnum:]].

How do I get capture groups in Bash?

After [[ $s =~ re ]], use ${BASH_REMATCH[0]} for the full match and ${BASH_REMATCH[1]}, [2], etc. for groups.

Why do I only see one match?

If you don’t use flag g, the tool shows the first match only; add g to list all matches.

Can I test multiline patterns here?

Yes; paste multiple lines and use m for JS-style multiline behavior, but note Bash/grep may handle newlines differently.

Is my text uploaded anywhere?

No; everything runs locally in your browser and this tool does not make network requests.

Continue your workflow

Browse related tools by task. Use the improved core tools for a consistent workspace with file import, downloads and clear validation errors.