use strict;
my $str = 'A0ihO, gIUW4, Kh6Xp, sYAXL, IZvuE, PtQvw, zeSEt, YsCo0, WfzbU, 5TTIz, oKTOO, qaaTK, y4QUd, C4vNY, lDplP, Gjrg8, UHzUT, 32ZcV, c7xgl, 5Lr2H, fDgxt, zFdYO, hohuK, vrNU4, 8oRg5, IYcyl, pblbO, SHhq0, yFjWa, rzYLr, m2AXf, QdhtM, TWpkh, 4499K, 5Bcv8, 0DeqI, 6BdTy, fJgKX, tUZeh, HPso5';
my $regex = qr/((?:[^,]*,){10}) /p;
my $subst = '\\1\\n';
my $result = $str =~ s/$regex/$subst/rg;
print "The result of the substitution is' $result\n";
Please keep in mind that these code samples are automatically generated and are not guaranteed to work. If you find any syntax errors, feel free to submit a bug report. For a full regex reference for Perl, please visit: http://perldoc.perl.org/perlre.html