Perl - tailing a file

[idx]

So I'm looking to create some utilities to watch various logs/etc and perform actions when certain criteria is found in the files. I have a basic example working, but if the log is truncated a certain way, the script doesn't detect the file change. Any ideas?

cat /dev/null > logfile

After something like that it doesn't catch the first addition.

I also ran across the File::Tail module, but would rather have all the code self contained instead of having external requirements..

use File::stat;
use IO::Handle;

$| = 1;

$file = '/tmp/foo1';

open(FH, $file) or die "$!\n";

for (;;) {

   while(<FH>) { print }

   sleep 1;

   if (stat(*FH)->nlink == 0) {
      print "=== new FH\n";
      close(FH);
      open(FH, $file) or die "$!\n";
      sleep 5;
   }
   else {
      seek(FH, 0, 1);
   }

#   print "=== end for pos=" . tell(FH) . "\n";
}

close(FH);

I was also planning on watching the inode and filesize (for shrinking) and if they change, to close the FH and reopen. Any cool ideas or should I just give up and use the module?

-r

[ender]

It would appear that you already have some external requirements: File::Stat and IO::Handle. I do not deny that doing everything by hand is a fun rich experience to learn from, however, I do believe that if you are already using these modules: what is the harm in adding another one?

If you decide that you still want to do it the fun way, just say so. We are here to help.

I also like to do things the hard way and tend to always implement stuff myself for personal projects.

-Ted

[idx]

Not sure how well/poor those modules are supported, but they seemed to be in every perl build I tested this on. (freebsd, linux and aix.. each on a different perl version) The main issue with adding the other module is ease of distribution to numerous systems without installing a bunch of stuff. The main kicker is that File::Tail requires Time::HiRes which needs to be compiled. Can't just do a simple use lib '/foo'; and include the module as part of my code..

ack.. gotta get some sleep.

-r