Hello monks!
maybe this question is dangerous/stupid but I'm in a blind-way..
I wont to modify the source of the script I'm executing refreshing the value of a variable so that next time I run that code smartly.I don't wont to use another file.

open (PROG, ">>$0");
seek (PROG, 0, 0);     #not working 
while (<PROG>)
{
  if ($_=~/$\$data=/){s/\$_/\$data=$new_value;/}
}
close (PROG);
[download]

If I try with this code above the new resulting code is double (the second with a funny shabang). Seek seems not work (if I try, after seek to print "hello", it print it at the end of the file).Maybe my regex is terrible(I had split for now the substitution)..
Some ideas?

greetings lorenzo*