Is it a one-time search? If so, read one line at a time, look for the pattern you want, and then extract the last value. The above comment by ikegami would be a good way of doing that. If you need to repeatedly search for different lines, then you would need to do something more like what swampyankee suggests. Or you could build a hash with the first column as keys (assuming they're unique) and the last column as values, like this:

while(<FILE>) {
    my($key, $data) = /^(\S+).*\s(\S+)$/;
    $hash{$key} = $data;
}
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