PKGBUILDs/community/pacupdate/pacupdate.install

pkgname=pacupdate

post_install() {
  cat << EOM
>>> To allow pacupdate synchronize the databases you must:
>>>   1. Run visudo as root:
>>>      # visudo
>>>   2. Add the following line at the end of the file:
>>>      user    ALL=(ALL) NOPASSWD: /usr/bin/pacman -Sy
EOM
}