1926 1926document as opposed to $(document
http://perldoc.perl.org/perlvar.html

$(
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The real gid of this process. If you are on a machine that supports membership in multiple groups simultaneously, gives a space separated list of groups you are in. The first number is the one returned by getgid() , and the subsequent ones by getgroups() , one of which may be the same as the first number.