PREUN

/bin/sh

if [[ "$1" = "0" ]]; then
  perl -ni -e "/^DICT\s*mg\s*MG\s*mg_MG$/ or print" /usr/share/dict/ooo/dictionary.lst
fi

POSTIN

/bin/sh

if [[ ! -f "/usr/share/dict/ooo/dictionary.lst" ]] ||       ! grep -q "^DICT[ \t]*mg[ \t]*MG[ \t]*mg_MG" /usr/share/dict/ooo/dictionary.lst
then
  echo "DICT mg MG mg_MG" >> /usr/share/dict/ooo/dictionary.lst
fi