Question

I’m trying to assemble a script that will first identify the newest log file created under a folder, then open it and look for specific data. Basically, I will be looking in this log file for a specific error and print the errors into the new log file.

I understand how to perform sort in order to have the most recent file, but having trouble in reading the latest file and copying it to the new log file

use File::stat;

$dirname  = 'C:/Luntbuild_Logs';
$timediff = 0;

opendir DIR, "$dirname";

while ( defined( $file = readdir(DIR) ) ) {
    if ( $file ne "." && $file ne ".." ) {
        $diff = time() - stat("$dirname/$file")->mtime;
        if ( $timediff == 0 ) {
            $timediff = $diff;
            $newest   = $file;
        }
        if ( $diff < $timediff ) {
            $timediff = $diff;
            $newest   = $file;
        }
    }
}

print $newest;

$file1 = "$dirname/$file";

open( FILE1, "<$newest" );
my (@fprint) = <FILE1>;
close FILE1;

open( FOUT, ">list1.txt" ) || die("Cannot Open File");

foreach $line (@fprint) {
    print "$line" if $line =~ /> @/;
    print "$line" if $line =~ /ORA-/;
    print FOUT $line;
}

close FOUT;

Answer 1

The primary problem is that you build the full file path in $file1 but then open $newest which contains only the file name.

You really should improve your code by

• Always using use strict and use warnings at the start of your program, and declaring all variables with my at their point of definition

• Use lexical file and directory handles and the three-parameter form of open. Always test the status of an open and put $! in the die string so that you know why it failed

• Never put double-quotes around a variable unless you know what it does and that is what you want

Here is a refactoring of your code which follows these guidelines and also uses the built-in -M operator that returns the age of a file in days

use strict;
use warnings;

my $dirname = 'C:/Luntbuild_Logs';
my ($newest_age, $newest_file);

opendir my $dh, $dirname or die $!;

while ( readdir($dh) ) {
  my $file = "$dirname/$_";
  next unless -f $file;
  my $age = -M $file;
  unless (defined $newest_age and $newest_age <= $age) {
    $newest_age = $age;
    $newest_file = $file;
  }
}

print $newest_file, "\n";

open my $out,'>', 'list1.txt' or die "Cannot open file: $!";

open my $in, '<', $newest_file or die $!;
while (<$in>) {
  print if /> \@/ or /ORA-/;
  print { $out } $_;
}

close $out or die $!;
close $in or die $!;