Thank you very much for the explanation...appreciate your efforts. Script is working great for me I have updated the script a little as per my requirements.

#!/usr/bin/perl
use Data::Dumper;
use File::Copy;
use feature qw{ say };

my %replacementLU = (
   QOS_PROFILE_ID                 => q{x1},
   CHARGING_PROFILE_ID            => q{x2},
   CONTENT_FILTERING_PROFILE_ID   => q{x3},
   SUBSCRIBERID                   => q{x4},
   RECORD_LENGTH                  => q{x5},
   RECORD_TYPE                    => q{x6},
   EVENT_ID                       => q{x7},
   EVENT_RESULT                   => q{x8},
   CAUSE_PROTOCOL                 => q{x9},
   DEFAULT_BEARER_ID              => q{x0},
   ARP_PRIORITY_LEVEL             => q{y1},
   ARP_CAPABILITY                 => q{y2},
   ARP_VULNERABILITY              => q{y3},
   BEARER_CONTROL_MODE            => q{y4},
   TRACKING_AREA_CODE             => q{y5},
   ROUTING_AREA_CODE              => q{y7},
   SERVICE_AREA_CODE              => q{y8},
   SYSTEM_IDENTIFIER              => q{y9},
   NETWORK_IDENTIFIER             => q{y0},
   GX_RAR_RAA_TRANSACTION         => q{TRAR},
   GX_CCR_CCA_TRANSACTION         => q{TCCA},
   QUOTA_GRANTED                  => q{TQG},
   QOS_ASSIGNED_TO_DEFAULT_BEARER => q{TQA},
   RULE_INSTALLED                 => q{TRI},
   RULE_REMOVED                   => q{TRR},
   );

my $subsRE = do {
   local $" = q{|};
   qr{(?x) \b ( @{ [ keys %replacementLU ] } ) \b};
   };

my $counter = 0;
open (WFH1, ">", "counter.txt");

for( ; ; )
{
my $fileexists= -e "text.out";

if ($fileexists ne "1")
{
`touch text.out`;
foreach my $file (</data/admin/scripts/SapcmedadpebM/test/*csv>)
{
chomp;
$abc1=`find $file -mmin +10`;
chomp($abc1);
if ($abc1 eq "")
{
next;
}
print " file $abc1 \n";
$dd=`date`;
print "$dd\n";
`perl -i -pe 's/[^[:ascii:]]//g; tr/\015//d' $abc1`;
print "junk character removed\n";

open (FH, "$abc1");
open (WFH, ">", "abc1.op");

while (<FH>) {
$_ =~ s{$subsRE}{$replacementLU{ $1 }}g;
print WFH $_;
}

#`sed -i 's/QOS_PROFILE_ID/x1/g;s/CHARGING_PROFILE_ID/x2/g;s/CONTENT_F
+ILTERING_PROFILE_ID/x3/g;s/SUBSCRIBERID/x4/g;s/RECORD_LENGTH/x5/g;s/R
+ECORD_TYPE/x6/g;s/EVENT_ID/x7/g;s/EVENT_RESULT/x8/g;s/CAUSE_PROTOCOL/
+x9/g;s/DEFAULT_BEARER_ID/x0/g;s/ARP_PRIORITY_LEVEL/y1/g;s/ARP_CAPABIL
+ITY/y2/g;s/ARP_VULNERABILITY/y3/g;s/BEARER_CONTROL_MODE/y4/g;s/TRACKI
+NG_AREA_CODE/y5/g;s/ROUTING_AREA_CODE/y7/g;s/SERVICE_AREA_CODE/y8/g;s
+/SYSTEM_IDENTIFIER/y9/g;s/NETWORK_IDENTIFIER/y0/g' $abc1`;
#`sed -i 's/GX_RAR_RAA_TRANSACTION/TRAR/g;s/GX_CCR_CCA_TRANSACTION/TCC
+A/g;s/QUOTA_GRANTED/TQG/g;s/QOS_ASSIGNED_TO_DEFAULT_BEARER/TQA/g;s/RU
+LE_INSTALLED/TRI/g;s/RULE_REMOVED/TRR/g' $abc1`;
move("abc1.op","./$abc1");
$counter++;
print WFH1 $counter;
}

unlink "text.out";
}
else
{
print "Exiting \n";
exit;
}
sleep(100);
}
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Now when I execute this script to process a 400Mb i/p file (which it the required size) after generating 300Mb of output data it sticks.. doesn't throw any error, or doesn't fail..it just stops generating output data. Then I tried with a 200Mb file and again it stuck at 160Mb.. without any error message I am not able to find the root cause.. could it be a memory issue? could you please suggest any thing which can help us get this issue resolved? Please let me know if you need more info...thnaks