I'm not sure what the problem is, exactly. Do you want to just know when the program has finished reading?

use strict;
use warnings;
my $file = "file.txt";
open FH, "<", $file;
while(<FH> {
# do something here...
}
print "End of file has been reached\n";
[download]

I think that ought to do it for you, though I haven't actually tested the code.