open IN, "infile.dat";
open OUT, ">data.csv";

while (<IN>) {
    chomp $_;
    my @fields = split(/|/, $_);
    my $newLine = join(",", @fields);
    print OUT "$newLine\n"
}
close IN;
close OUT;

##</code><code>##

hi|I'm with GNU,Inc.|I need a comma in my title
this|will|produce|,|to|many|fields