Problems:

• /[4]/ matches "4", not "[4]".

• You never exit the inner loop before the end of the file.

• $errorCode != 0 || $errorCode != 1
  should be
  $errorCode != 0 && $errorCode != 1
  The former is always true.

• die ... unless -f "$logFile"; is useless, even harmful. open not only performs this check, but can provide a better error message.

• You call <> (in the outer loop) after being told you've reached the end of the file (in the inner loop).

• \[ is more usual and readable than [[]
  \] is more usual and readable than []]

• while (...) { ...; next }
  is the same as just
  while (...) { ...; }

Fix:

use strict;
use warnings;

my $ArcotIDError_Count = 0;

OUTER:
while(my $line = <>) {
    $line =~ tr/\r\n//d;
    next if $line !~ /Handling NSPAdvice for mechanism \[4\]/;

    do {
        $line = <>;
        last OUTER if !defined($line);
    } while $line !~ /Authentication mechanism returned \[(\d+)\]/;

    my $errorCode = $1;
    #print("\$errorCode=$errorCode\n");
    if ($errorCode != 0 && $errorCode != 1) {
        $ArcotIDError_Count++;
    }
}

print "Total Number Of ArcotID Authentication ErrorCode returned is $A
+rcotIDError_Count\n";
[download]

( I see that others have identified some of the issues, but not all. )

Update: Reordered points by descending severity.

Hi, Sorry, i am getting diffrent output when i run Ikegami script and my script with chnages. I am getting 142 for Ikegami and 352 for my script. Thanks NT

Like I said, the other monks only found some of the problems in your script. Your script counts errors that aren't for "Handling NSPAdvice for mechanism [4]".

For example, for the following log, your script counts two errors and mine counts one:

...Handling NSPAdvice for mechanism [4]...
...Authentication mechanism returned [3]...
...Handling NSPAdvice for mechanism [5]...
...Authentication mechanism returned [3]...
[download]

This is a symptom of your inner loop not exiting before the end of the log file (the second bullet in the grandparent post).

Maybe \d+ is too restrictive? If you can have negative numbers, change it to -?\d+

Hi , I got it. You guys are wonderful. Thanks NT

You need to change:

if($line =~ /Handling NSPAdvice for mechanism [4]/) {
[download]

to

if($line =~ /Handling NSPAdvice for mechanism \[4\]/) {
[download]

because the character [ is special in a regular expression.

Update: Your logic in the statement:

if ($errorCode != 0 || $errorCode != 1) {
[download]

is flawed because an $errorCode with any number will pass this test.   You probably meant:

if ($errorCode != 0 && $errorCode != 1) {
[download]

Hi , Thanks for your reply, that part got reolved, but i am not getting the desired output. I need to count all except 0 and 1 for mechanism, but in the output file, i can see all are printed and counted.Some logic problem i guess. Please suggest me what i am doing wrong. Thanks NT

You need to escape the square brackets since you want to match a literal [4], so instead of

    if($line =~ /Handling NSPAdvice for mechanism [4]/) {
    # the RE above would match "Handling NSPAdvice for mechanism 4"
[download]

    if($line =~ /Handling NSPAdvice for mechanism \[4\]/) {
    # alternative: if ( index($line,'Handling NSPAdvice for mechanism 
+[4]')>=0 ) {
[download]

            if ($line =~ /Authentication mechanism returned [[](\S*)[]
+]/) {
[download]

            if ($line =~ /Authentication mechanism returned \[(\-?\d+)
+\]/) {
            # the RE above would match e.g. [4] -> $1=4,  [-10] -> $1=
+-10, etc.
[download]

jwkrahn's suggestion fixes your problem, but might I also suggest you change your second regex? It's difficult to read for what it does.

$line =~ /Authentication mechanism returned \[(\d+)\]/
[download]

OK, so it's not that much easier to read...

The first thing is to determine whether or not we have the right number of arguments. In Perl this the number of elements in @ARGV.

Then normally statement(s) follow that assign the @ARGV elements to $scalar values.

Then these values are used. Update: to open file(s)

This is a general "formula or pattern" for your Perl programs.

#!/usr/bin/perl -w
use strict;

#my $logFile = $ARGV[0]; 
#die "usage: $0 <logFile>" unless $logFile; 
#die "Logfile $logFile doesn't exist" unless -f "$logFile"; 
#open(my $log, "<", $logFile) or die "Can't open $logFile for reading.
+"

die "Wrong number of args\nUsage: $0 Logfile" if (@ARGV != 1);
my ($logFile) = @ARGV;
open(my $log, "<", $logFile) || die "Can't open $logFile for reading";
[download]