#!c:\perl\bin\perl -w use strict; # you know you wanted this, right? open(NB, "nbt.csv") or die "Can't open input nbt.csv\n"; # NBT.CSV simply contains ip addresses - one per line while() { chomp $_; my $line="$_".","; # using my eliminates the undef my @nbtstat = `nbtstat -a $_`; # my will make you happy for ($j=0; $j<=$#nbstat;$j++) # $# is the last index { my $short=substr($nbtstat[$j],0,15); chomp $short; unless ($line=~m/$short/) {$line=$line.",".$short;} } print "$line\n"; } close(NB);