Dangerous behavior to keep user and password in a command instead of a protected secret file

Since 
`AUTH="--user=${USERNAME} --password=${PASSWORD}"`
will expose the user and password information in the system by `ps` and in the command history, strongly suggested to rewrite related code by using wgetrc or other ways for downloading the files in the data hubs.
Especially for those large files, the user and password is visible through easy `ps ax | grep wget` which is very dangerous.
