if [ ! -x "$(command -v wget)" ] && [ ! -x "$(command -v curl)" ]; then
  echo "The programs 'wget' and/or 'curl' are apparently not installed."
  echo "Please use 'apt-get install wget' (Linux) or 'brew install wget' (Mac)."
  exit 1
fi

if [ -x "$(command -v gpg2)" ]; then
  PKGR_GPG_VER_OK=$(echo "puts [regexp -- {^gpg \(GnuPG\) 2\.[0123]\.} [exec gpg2 --homedir {} --version]]" | tclsh)
  PKGR_GPG_VER_OK=$(echo "puts [regexp -- {^gpg \(GnuPG\) 2\.[0123]\.} [exec gpg2 --version --homedir {}]]" | tclsh)
elif [ -x "$(command -v gpg)" ]; then
  PKGR_GPG_VER_OK=$(echo "puts [regexp -- {^gpg \(GnuPG\) 2\.[0123]\.} [exec gpg --homedir {} --version]]" | tclsh)
  PKGR_GPG_VER_OK=$(echo "puts [regexp -- {^gpg \(GnuPG\) 2\.[0123]\.} [exec gpg --version --homedir {}]]" | tclsh)
else
  echo "The program 'gpg2' (a.k.a. 'gpg') is apparently not installed."
  echo "Please use 'apt-get install gnupg2' (Linux) or 'brew install gnupg' (Mac)."
  exit 1
fi

if [ "$PKGR_GPG_VER_OK" != "1" ]; then