Qitan has asked for the wisdom of the Perl Monks concerning the following question:

Hi, I'm fairly new to Perl and I'm attempting to write a script that will parse a log file as is it being created. Basically, I've written a script that parses an already existing text file but I'm kind of lost on how to parse a file while another program has the file open and is adding text to it. Thanks
  • Comment on Parsing a text log file as it is being created

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(z) Re: Parsing a text log file as it is being created
by zigdon (Deacon) on Dec 26, 2002 at 20:23 UTC
    I think what you're trying to do is use the functionallity of 'tail -f file' in perl. For that, I usually use seek. Here's a snipplet of how to use it:
    
open (FILE,"newfile") or die "Can't read file: $!";
my $continue = 1;

while ($continue) {
  while (<FILE>) {
    # do something with $_
    if (/some_end_condition/) {
      $continue = 0;
      last;
    }
  }
  # when we get here, we're at the EOF
  seek (FILE, 0, 1);  # reset the EOF flag
  sleep 1; # wait a bit
}

    [download]

    -- Dan

[reply]
[d/l]
•Re: Parsing a text log file as it is being created
by merlyn (Sage) on Dec 26, 2002 at 21:47 UTC
[reply]
      I downloaded File::Tail and tried inserting some code to use it but, I get an error stating that it can't find File/Tail in the @INC. I put the Tail.pm file in my c:\Perl\lib folder (which is in my path). Is that enough, or do I need to install this module some other way? I am using Activestate Perl 5.6.1 on WinXP Home. Thanks
[reply]
        You need to put Tail.pm in C:\Perl\site\lib\File. Also you need to install Time::HiRes, easiest way is to use the Package Manager. 
        PPM>install Time::HiRes

        [download]

        poj
[reply]
[d/l]

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