It seems that on DOS, the line endings are not recognized, thus the whole content ends up as a single logical line in your program.

Since I don't have DOS available I can't test my suggestion, but after reading Perlio I guess a binmode F, ":raw";

After the line with the open should help.

By the way you should always check if system calls like open() actually succeed:

open my $f, '<', 'text.txt'
   or die "can't open file 'text.txt' for reading: $!";
binmode $f, ':raw';
while (<$f>) {
   print "Result: $1" if /particularly(.*)/;
}
[download]