In order for cURL to use those credentials you will need to create a .netrc file.

To create a .netrc file, you will need to create a text file with the name .netrc; this file needs to have read permissions set to only yourself, so that no one can read your file and get your username and password. The format of the file is:

machine urs.earthdata.nasa.gov login <username> password <password>

where <username> and <password> are the values you set when you created your Earthdata login account.