One way is to take advantage of excel's ability to open tab delimited text files with .xls extension

#!perl
use strict;
open OUT,">test.xls" or die "$!";
while (<DATA>){
  s/;;/\t/g;
  print OUT;
}
close OUT;

__DATA__
abd;;sasa;;trre,dsa;;sdas;;dsss
abd;;sasa;;trre,dsa;;sdas;;dsss
abd;;sasa;;trre,dsa;;sdas;;dsss
[download]

hey the thing is i need the output as csv , because it is an input to other sub routine

I would change the other routine, but anyway, a simple solution would be double quote all the fields regardless.

#!perl
use strict;
open OUT,">test.csv" or die "$!";

while (<DATA>){
  chomp;
  s/;;/","/g;
  print OUT '"'.$_.'"'."\n";
}
close OUT;

__DATA__
abd;;sasa;;trre,dsa;;sdas;;dsss
abd;;sasa;;trre,dsa;;sdas;;dsss
[download]

poj