[MacPerl] editing text files

[Timothy Duke]

Hi,
I have got two versions of a script to eliminate single line-feeds from 
a file.  The first one does weird stuff - duplicating lines and messing 
the text file up.  The second one works (I copied it from a Perl guide), 
but I don't understand why.  I would much prefer the first one to work - 
Can you tell me how to change the first one to make it work?

Also, I understand that the <> operator reads in one line at a time.  If 
I wish to eliminate only triple line-feeds (\n\n\n) and leave double and 
single linefeeds, I presume <> won't work.  Without reading in the whole 
file at once, how can I achieve this?

I am using MacPerl.
Thanks for any help!
Tim
----------------------------------------------------
Version #1 (works dreadfully....stuffs up the file)
#! perl  -w -i
$filetobechanged = "iBook HD:Desktop Folder:tim.txt";
open(FILE, "+< $filetobechanged") ;
while (<FILE>) {
    s/\n//g;
    print FILE ;
        }
close(FILE);
Version #2 (works fine)
$filetobechanged = "iBook HD:Desktop Folder:tim.txt";
@ARGV = ($filetobechanged);
$^I = ".bak";
while (<>) {
    s/\n//g;;
    print;
}