Hmmm... if this is the entire script, you could simply pass the filename as a parameter and use the -p and -i switches, something like this:

#/usr/bin/perl -pi.bak
$count++ if s/^go/\//;

END { print STDERR "There were $count lines starting with 'go' in the 
+file\n"; }
[download]

This will automatically overwrite your original file with the new, substituted lines. It will also create a backup file named "<file>.bak" just in case. :-)

If this is not your entire program, then you can just capture its output to a new file, then rename the new file to have the same name as the old one. You could have your program do this itself by printing its output to a new file, then renaming that file. Maybe something like this (this is not the whole program, of course):

open FILE, "< $file" or die "Can't open input file: $!\n";
open OUT, "> '$file.new'" or die "Can't open output file: $!\n";
while (<FILE>) { 
    $count++ if s/^go/\//;
    print OUT;
}
close OUT;
close FILE;
print STDERR "There were $count lines starting with 'go' in the file\n
+";
rename $file, "$file.bak";  # make backup copy
rename "$file.new", $file;  # overwrite original file
[download]

-- Mike

--
just,my${.02}