reading from line X in perl

[Ciary]

hi all,

i recently encountered a problem about something that should be really easy but in fact i couldn't find any information on how to do it.
what i want to do is read a logfile in perl. i open the file, read the data, parse it, then close the file. so far so good.
now, while the script is running, i append a few lines to the logfile. i now want perl to somehow remember at which line it last read, and when i open the file i want to jump to the end and read only the new lines.
the reason for this is that i might have huge logfiles and reading them completely all the time won't work fast enough.

$exitfile = '/path/to/the_exit_file';
while (!(-e $exitfile)) {
    print "and we read?\n";
 
    open(DAT, "/path/to/mylog.log") || die("Could not open file!");    
    foreach $line (<DAT>) {
        chomp($line);
        print $line;
    }   
    close(DAT);
    sleep(1);
}
 

in this case, i keep opening the file every second and reading it all the way through until i create a certain file (the exit file)
anyone know how i can just read the new lines?
what i was thinking was counting the lines in my foreach loop, but then i have the problem of not being able to move my pointer to that location.
thanks!

[Ciary]

forget it, searched for 3 hours, posted this, then 10 minutes later i had a solutions

$exitfile = '/path/to/the_exit_file';
my $pointerPos = 0;
while (!(-e $exitfile)) {
    print "and we read?\n";
 
    open(DAT, "/path/to/mylog.log") || die("Could not open file!");    
    seek DAT, $pointerPos, 0;
    foreach $line (<DAT>) {
        print $line;
    }   
    $pointerPos = tell DAT;
    close(DAT);
    sleep(1);
}
 

just "tell" to ask the position in bytes and "seek" to move the pointer back to that position. also the last 0 in seek means you start $pointerPos byes from the START of the file. you can also put seek from the end of the file.