pcre - How to use non-capturing groups in grep?

Question

This answer suggests that grep -P supports the (?:pattern) syntax, but it doesn't seem to work for me (the group is still captured and displayed as part of the match). Am I missing something?

I am trying grep -oP "(?:syntaxHighlighterConfig.)[a-zA-Z]+Color" SyntaxHighlighter.js on this code, and expect the results to be:

wikilinkColor
externalLinkColor
parameterColor
...

but instead I get:

syntaxHighlighterConfig.wikilinkColor
syntaxHighlighterConfig.externalLinkColor
syntaxHighlighterConfig.parameterColor
...

Answer 1

"Non-capturing" doesn't mean that the group isn't part of the match; it means that the group's value isn't saved for use in back-references. What you are looking for is a look-behind zero-width assertion:

grep -Po "(?<=syntaxHighlighterConfig.)[a-zA-Z]+Color" file