I've got a program online that does insertion into a file (http://www.pobox.com/~japhy/tmp/perl/add_lines). But the bigger question is, WHY DO YOU NEED TO DO THIS? Observe:

open FILE, ">>data" or die "can't append to data: $!";
print FILE "NEW RECORD\n";
close FILE;

# now, to store the file's contents in an array, MOST
# RECENT DATA FIRST, use unshift instead of push!

open FILE, "data" or die "you know the drill... $!";
unshift @contents, $_ while <FILE>;
close FILE;
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