RE: Tail -f and select - Again

[Jonathan Pelletier]

On my side, I prefer not to use the System TAIL at all... Instead, i use a
simple open, and I restart the loop each time the end of file is reached...

There is a small example...


#!/usr/bin/perl -w
use strict;
use IO::File;

my $FILENAME = './test.txt';

my $FH = new IO::File;
$FH->open($FILENAME) or die "open Failed\n";

while($FH)
  {
    while(my $line = <$FH>)
      {
        print "READ: $line";

        # Exit the loops if "last" is found
        if($line =~ /last/)
          {
            close $FH;
            $FH = undef;
            last;
          }
      }
    sleep 1; # sleep for 1 sec each time the end of file is reached
  }
print "\n\n Script Exit \n\n";





I hope this can be usefull to you ;-)



-----Original Message-----
From: Mark Borghardt [mailto:[EMAIL PROTECTED]]
Sent: 22-Jan-2002 13:18
To: '[EMAIL PROTECTED]'
Subject: Tail -f and select - Again



Sorry if this is a rehash (no Perl pun intended) of a subject already
covered, but I have read all of the archived messages and scoured the net
for a solution to my problem with no success.

What I want to do is read data from a growing file (tail -f) until a special
record arrives, at which point I would like to close the file and reopen
another one repeating the process.

I almost got it to work with

$datafile="File1";
while () {
   open(DATAIN,"tail +0 -f $datafile |");
   while ( <DATAIN> ) {
       print $_;
       if (substr($_,0,4) eq "SPEC") {
           $datafile=substr($_,4);
           last;
       }
   }
   close(DATAIN);
}

Datafiles are all 9 characters and a <LF> per record and of the form:
Record 01
Record 02
SPECFile2

The only problem is that I have to hit <Control C> on the keyboard to kill
the old tail process.

Is there a way to send a signal to the open tail process so I don't have to
hit <control c> ?

Is there a better strategy for doing this?

Any help would be appreciated.

Mark Borghardt