#Vorher:
#
#MARIS|DOC|XXXXXX|CH2 endgültiger Arztbrief|XXXXX|XXXXX|8018221|XXXXX|XXXXX|20190527|null||null|20190527|ZWMAB
#
#Nachher:
#
#MARIS|DOC|XXXXX|CH2 endgültiger Arztbrief|XXXXX|XXXXX|8018221|XXXXX|XXXXX|20190527|200088||CH2|20190527|ZWMAB

my $line = "ARIS|DOC|XXXXXX|CH2 endgültiger Arztbrief|XXXXX|XXXXX|8018221|XXXXX|XXXXX|20190527|null||null|20190527|ZWMAB";
my @felder = split '|',$line;
if ($felder[3] =~ /(.+) /) {
  $felder[10] = 200088;
  $felder[12] = $1;
}