First of all, you should be using the bq command line tool to interact with BigQuery from the command line. (Read about it here and download it here).
I agree with Marc that it's a good idea to use your personal credentials with both gsutil and bq, the bq command line tool supports the use of service accounts. The command to use service account auth might look something like this.
bq --service_account [email protected] --service_account_credential_store keep_me_safe --service_account_private_key_file myfile.key query 'select count(*) from publicdata:samples.shakespeare'
Type bq --help for more info.
It's also pretty easy to use service accounts in your code via Python or Java. Here's a quick example using some code from the BigQuery Authorization guide.
import httplib2
from apiclient.discovery import build
from oauth2client.client import SignedJwtAssertionCredentials
# REPLACE WITH YOUR Project ID
PROJECT_NUMBER = 'XXXXXXXXXXX'
# REPLACE WITH THE SERVICE ACCOUNT EMAIL FROM GOOGLE DEV CONSOLE
SERVICE_ACCOUNT_EMAIL = '[email protected]'
f = file('key.p12', 'rb')
key = f.read()
f.close()
credentials = SignedJwtAssertionCredentials(
SERVICE_ACCOUNT_EMAIL,
key,
scope='https://www.googleapis.com/auth/bigquery')
http = httplib2.Http()
http = credentials.authorize(http)
service = build('bigquery', 'v2')
datasets = service.datasets()
response = datasets.list(projectId=PROJECT_NUMBER).execute(http)
print('Dataset list:\n')
for dataset in response['datasets']:
print("%s\n" % dataset['id'])