File::ReadBackwards

Description: File::ReadBackwards works similar to the linux shell command tac. It reads the file line by line strarting from the end of the file.

CPAN: File::ReadBackwards

Example 1:
Being a System’s Administrator, I am usually doing some analysis on a large logfile. Therefore, I may not need all the information contained in the log. This may be especially true if the logs only get rotated once a day or once a week and I don’t need all the information in the log file. Using File::ReadBackwards in combination with a date and time calculation module, I can take only the amount of time I want to use from the logs and then stop processing there. Since we aren’t covering the date calculations here, I will push those out to another subroutine that we will assume works.

# Always use these
use strict;
use warnings;

# Use the module itself
use File::ReadBackwards;

# Define the log file to be read
my $log = "/var/log/log_file";

# Open the logfile by tie'ing it to the module
tie *LOG, "File::ReadBackwards", "$log"
   or die ("$log tie error: $!");

# Iterate over the logfile
while (my $line = ) {

  # Split the log line
  my @entry = split(/\s+/, $line);

  # Take the timestamp and check if we
  #   have hit our threshold yet
  # Break loop if we have
  last if (time_reached($entry[0]) == 1);
}

# Cleanup
untie (*LOG);