AWS credentials environment variable has changed

[edgewood]

s3cmd looks for the AWS_CREDENTIAL_FILE environment variable to find the AWS credentials in the absence of a s3cmd config file. However, newer versions of awscli (1.7.45 and later) use a different environment variable, AWS_SHARED_CREDENTIALS_FILE See
https://docs.aws.amazon.com/cli/latest/userguide/cli-configure-envvars.html

As a workaround, export AWS_CREDENTIAL_FILE=$AWS_SHARED_CREDENTIALS_FILE works for me with a very simple AWS setup, but there could be other changes to the file structure in other setups.

As an aside, I discovered this issue trying to use AWS credentials as a workaround for s3cmd's lack of support for the XDG basedir spec (#658).