Seems to be a combination of Regexp::Common and Named captures.

This : %{NUMBER:duration} %{IP:client} is equivalent to something like: 

$str =~ m[(?P<duration>$RE{num}{real})(?P<client>$RE{net}{IPv4})];

print "Client:$+{client} duration:$+{duration}";

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In reply to Re: Equivalent of grok in perl by BrowserUk
in thread Equivalent of grok in perl by casimir9_official

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