$ perl -le '
> $txt = qq{abc\tdef,\tghi\tjkl\tmno};
> print for split m{[^,]\t}, $txt;
> print q{-} x 20;
> print for split m{(?<!,)\t}, $txt;'
ab
def,	gh
jk
mno
--------------------
abc
def,	ghi
jkl
mno
$