You want to match 

name, dash, name, dash, name

[download]

or 

( name, dash ) x 2, name

[download]

so 

my ($substr) = $s =~ /^((?:[^_]*_){2}[^_]*)/
    or die("No match\n");

[download]

In reply to Re^3: Quick regex by ikegami
in thread Quick regex by Karger78

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