If it's a Linux/Unix system you can use the system's tool grep:

grep PATTERN FILE_TO_SEARCH_IN > FILE_WITH_SEARCH_RESULTS
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More info can be found in the manpage of grep.

a simple perl solution could look like this (using some perl magic):

#!/usr/bin/perl
use strict;
use warnings;

my $pattern = shift @ARGV;

while (<>) {
    print if m/$pattern/;
}
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Save that to a file and execute it this way:

perl script.pl PATTERN FILE_TO_SEARCH_IN > FILE_WITH_SEARCH_RESULTS
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update:
formatting changes
perl example added