if [ "$EA" = "VA" -a "$EB" = "VB" ]; then
  echo EA == VA AND EB == VB
fi

if [ "$EA" != "VA" -a "$EB" = "VB" ]; then
  echo EA != VA AND EB == VB
fi

if [ "$EA" = "VA" -a "$EB" != "VB" ]; then
  echo EA == VA AND EB != VB
fi

if [ "$EA" != "VA" -a "$EB" != "VB" ]; then
  echo EA != VA AND EB != VB
fi

if [ "$EA" = "VA" -o "$EB" = "VB" ]; then
  echo EA == VA OR EB == VB
fi

if [ "$EA" != "VA" -o "$EB" = "VB" ]; then
  echo EA != VA OR EB == VB
fi

if [ "$EA" = "VA" -o "$EB" != "VB" ]; then
  echo EA == VA OR EB != VB
fi

if [ "$EA" != "VA" -o "$EB" != "VB" ]; then
  echo EA != VA OR EB != VB
fi