Use backward reference in match operator in PowerShell

Asked Aug 14 '19 at 19:54

Active Aug 14 '19 at 19:54

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I can use backward reference in -Replace operator in PowerShell. For example, this code

'abc456' -Replace '(abc)\d*', '$1def'

returns abcdef. But I would like to use it not only with -Replace operator but also with -Match to check whether some string satisfies a regular expression. Something like this

'aa' -Match '[a]$1'

But the code above returns false. Is it possible to use backward reference with -Match operator?

asked Aug 14 '19 at 19:54

Артур Гудиев

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`'aa' -Match '(a)\1'`? – Wiktor Stribiżew Aug 14 '19 at 19:55
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`\1` is not a backword reference, it is an inline backreference, and it is supported by .NET regex. Actually, all these basic constructs are already dealt with [Reference - What does this regex mean?](https://stackoverflow.com/questions/22937618/reference-what-does-this-regex-mean). – Wiktor Stribiżew Aug 14 '19 at 19:56
@WiktorStribiżew yes, thanks! – Артур Гудиев Aug 14 '19 at 19:57
@WiktorStribiżew if you write an answer below I will accept it – Артур Гудиев Aug 14 '19 at 19:58
`'aa' -Match '(?a)\k'` would be the named alternative. See [Backreference Constructs in Regular Expressions](https://learn.microsoft.com/dotnet/standard/base-types/backreference-constructs-in-regular-expressions). – Lance U. Matthews Aug 14 '19 at 20:00

Use backward reference in match operator in PowerShell

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