append a text on the top of the file

Question

I want to add a text on the top of my data.txt file, this code add the text at the end of the file. how I can modify this code to write the text on the top of my data.txt f

Answer 1

Your syntax is slightly off deprecated (thanks, Seth):

open(MYFILE, '>>', "data.txt") or die $!;

You will have to make a full pass through the file and write out the desired data before the existing file contents:

open my $in,  '<',  $file      or die "Can't read old file: $!";
open my $out, '>', "$file.new" or die "Can't write new file: $!";

print $out "# Add this line to the top\n"; # <--- HERE'S THE MAGIC

while( <$in> ) {
    print $out $_;
}
close $out;
close $in;

unlink($file);
rename("$file.new", $file);

(gratuitously stolen from the Perl FAQ, then modified)

This will process the file line-by-line so that on large files you don't chew up a ton of memory. But, it's not exactly fast.

Hope that helps.