#!/usr/bin/perl

# https://perlmonks.org/?node_id=1226189

use strict;
use warnings;

while( <DATA> )
  {
  my @queue = $_;
  while( @queue )
    {
    local $_ = shift @queue;
    if( /\|([^|,]*(?:,[^|,]*)+)\|/ )
      {
      push @queue, map "$`|$_|$'", split /,/, $1;
      }
    else
      {
      print;
      }
    }
  }

__DATA__
 some text FOO | some text BAR | oh , no , commas | some text BAZ | some text QUX
 some text FOO | some text BAR | single | some text BAZ | some text QUX
 some text FOO | some text BAR | oh , no , commas | one, two | some text QUX

##</code><code>##

 some text FOO | some text BAR | oh | some text BAZ | some text QUX
 some text FOO | some text BAR | no | some text BAZ | some text QUX
 some text FOO | some text BAR | commas | some text BAZ | some text QUX
 some text FOO | some text BAR | single | some text BAZ | some text QUX
 some text FOO | some text BAR | oh | one| some text QUX
 some text FOO | some text BAR | oh | two | some text QUX
 some text FOO | some text BAR | no | one| some text QUX
 some text FOO | some text BAR | no | two | some text QUX
 some text FOO | some text BAR | commas | one| some text QUX
 some text FOO | some text BAR | commas | two | some text QUX