Here.. MVC,CLI,BNE are keywords... wherever CLI comes, i need to append the next line along with the current line..

while (<>) {
 chomp if /^CLI\b/;
 print;
}
# or without all those default variables
while (my $line = <$FILEHANDLE>) {
 chomp($line) if $line =~ /^CLI\b/;
 print $line;
}
[download]

Probably not exactly what you had in mind, right? In either case you either want to check whether the line starts with "CLI" and chomp() it if it does or remember the last line (or whether it started with CLI) and append the text you read instead of adding a new element into the array.

my @lines;
my $last_line_was_CLI = 0;
while (<>) {
 chomp;
 if ($last_line_was_CLI) {
  $lines[-1] .= $_;
  $last_line_was_CLI = 0;
 } elsif (/^CLI\b/) {
  $last_line_was_CLI = 1;
  push @lines, $_;
 } else {
  push @lines, $_;
 }
}
[download]

Jenda
Enoch was right!
Enjoy the last years of Rome.

Perhaps this will do what you want to do?

use strict;
use warnings;

while (my $line = <DATA>) {
   if ($line =~ /CLI/) {
      chomp $line;
      while (my $line2 = <DATA>) {
         next unless $line2 =~ /\S/;  # ignore blank lines
         $line .= " $line2";
         last;
      }
   }
   print $line;
}

__END__
MVC   DOWO(8),WCPA   
                    
CLI   WCPA+2,C'.'  
                      
BNE   UPCC22
[download]

which prints

bash-3.2$ perl suno.pl
MVC   DOWO(8),WCPA   
                    
CLI   WCPA+2,C'.'   BNE   UPCC22     
bash-3.2$
[download]