our($opt_e,$opt_r,$opt_l,$opt_s,$opt_h,$opt_d,$opt_u, $opt_m, $opt_v, $opt_t,$opt_n);
my $option_spec ="e:r:l:s:u:v:t:hdm:n" ;
my $debug = 0;

unless(&getopts($option_spec,\%opt)) 

.....
.....
.....

print "OPT_V ===> $opt_v \n";
print "OPT_N ===> $opt_n \n";

if(defined $opt_v && $opt_v ne "" ){
                $ENV{ROOT} = $ENV{HOME}."/build_XX/".$opt_v if(defined $opt_n);
                $ENV{ROOT} = $ENV{HOME}."/build_AB/".$opt_v if(defined  $opt_n && $opt_n ne "");

}
else{
                $ENV{ROOT} = $ENV{HOME}."/build_XX/" if(defined $opt_n);
                $ENV{ROOT} = $ENV{HOME}."/build_AB/" if(defined $opt_n && $opt_n ne "");
}

print " ---- $ENV{ROOT} \n";
print "OPT_V ===> $opt_v \n";
print "OPT_N ===> $opt_n \n";