I was looking at Config::OpenSSH::Authkey and in its parse method I see this line: 
   if ( $data =~ m/^\s*(?:#|$)/ ) {

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Used to match blank or comment lines, I think.

I don't understand the usage of ?: in the grouping. Does not seem to make a difference in my testing.

So, what is the ?: for and why did they use it?

Also where is the construct "?:" documented? I have searched around but it is a hard term to search for.

Thanks in advance

In reply to Explain regex ?: usage in grouping by plc

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