See perlintro/perlopentut, basically 
open my($out), 'command |' or die $!;
print $out $_ while <$in>;
close $out;

[download]

Using system can be ok :) system "command < file";

In reply to Re: Newbie: Pipe/STDIN Clarification by Anonymous Monk
in thread Newbie: Pipe/STDIN Clarification by mpapet

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