If not already done, create the authorization object. See Example: Create an Authorization Object.
Run the READ_NOS command:
SELECT * FROM ( LOCATION='/s3/td-usgs-public.s3.amazonaws.com/CSVDATA/' AUTHORIZATION=MyAuthObj RETURNTYPE='NOSREAD_SCHEMA' ) AS d;
Your result will be similar to the following:
ColPosition 1 Name GageHeight2 Datatype decimal(3,2) FileType csv Location /S3/s3.amazonaws.com/td-usgs-public/CSVDATA/09513780/2018/06/27.csv ColPosition 2 Name Flow Datatype decimal(3,2) FileType csv Location /S3/s3.amazonaws.com/td-usgs-public/CSVDATA/09513780/2018/06/27.csv ColPosition 3 Name site_no Datatype int FileType csv Location /S3/s3.amazonaws.com/td-usgs-public/CSVDATA/09513780/2018/06/27.csv
The output is displayed vertically for readability.