line1
line1
line2
line1
line2
line3
[download]

This is what I got from your reply, but still not working, this time I get nothing:

while (<$tailf>) {
    chomp;
    my $line = $_;
    if($line =~ m/ on $ipaddress/)
    {
        if (scalar(@matches) <= 3){
            push(@matches, $line);
        }        
    }
    last;
}

foreach $line (@matches){
    print "$line\n";
}
[download]

Which loop are you talking about? foreach? Or do you mean the if conditions?

You can do this a lot easier and shorter:

open my $tailf, "tail -f $logFile |" or die;

for (1,2) {
    my $line = '';
    $line = <$tailf> until $line =~ / on $ipaddress/;
    push @matches, $line;
}
[download]

if($line =~ m/ on $ipaddress/)
    {
        if (scalar(@matches) <= 2){
            push(@matches, $line);
        }        
        else {
            exit(0);
        }
        foreach $line (@matches){
            print "$line\n";
        }
    }
[download]

if($line =~ m/ on $ipaddress/)
    {
        if (scalar(@matches) <= 2){
            push(@matches, $line);
        }        
        else {
            foreach $line (@matches){
                  print "$line\n";
            }
            exit(0);
        }
        
    }
[download]

That is not what I want. I want to save the line to the array if it matches the expression. I don't want to print anything this is just for debugging to make sure my array is containing the proper lines.

That is not what I want.

Sorry.... could have fooled me considering the logic in your original post.

If I break your code down into pseudo-code it reads like this:

open a pipe to the tail -f command for a logfile (unnamed)
iterate over the pipe

if less than 3 files are in array
if the line matches a (undetermined) IP address
push the line into an array
otherwise
exit the program
Iterate over the contents of the array
print line

Part of the art of getting good answers on Perl Monks is being concise about your questions and not leaving what you are after up to the interpretation of the reader.

Once again I will attempt to extrapolate what you are after. You code will work better if you don't put the print lines in and change the exit for last.

---

Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg

Is there a reason you are using "tail -f" in your file handle, as opposed to "tail -n 10" or similar. In my system, the script hangs waiting for additional input to the file. Here's an alternative idea for you to consider:

my @list;
my $file  = q[/path/to/some/file];
my $regex = qr[your pattern]; 
open my $fh, "tail $file |" or die;
while (<$fh>) {
    chomp;
    say "testing: $_";
    push @list, $_ if ( $_ =~ $regex);
    last if (@list >= 2);
}

local $"="\n";
say "found: @list";
[download]

The problem is I should be getting 2 lines but instead I get 6 lines? Any ideas what I'm doing wrong? to run it: ./script string

There must be six lines in the logfile you are tailing. Default behavior of the tail command is to list the last 10 lines in a file. This isn't really an array size issue at all.

This is a tail -f and the log file is a dhcp log so it has A LOT of lines not only 10 :)

dhcp log so it has A LOT of lines not only 10 :)

Here's a live example for you:

$ tail -f multtable.txt
0
9
18
27
36
45
54
63
72
81
[download]

The code that generated that was:

for ix in 0 1 2 3 4 5 6 7 8 9 
do
   for iy in 0 1 2 3 4 5 6 7 8 9 
   do
         n=`expr ${ix} '*' ${iy}`
         echo $n >> multtable.txt
   done 
done
[download]

That makes 100 lines. I do a "tail -f" and I see the last 10 lines all day long until someone writes to it. While I can't comment on the data set you are working with I can tell you about the behavior of most *nix commands.

---

Peter L. Berghold -- Unix Professional
Peter -at- Berghold -dot- Net; AOL IM redcowdawg Yahoo IM: blue_cowdawg