-- | get environment variable
getEnvDef :: String -- ^ environment variable
          -> String -- ^  default value
          -> IO String
getEnvDef envVar defValue = getEnvSave defValue envVar Just
getEnvDef :: String -- ^ environment variable
          -> String -- ^  default value
          -> IO String
getEnvDef envVar defValue = getEnvSave defValue envVar Just
getEnvDef envVar defValue = getEnvSave defValue envVar Just