AWS KMS – two liners

For binary encrypted output:

aws kms encrypt --region ap-southeast-2 --key-id alias/blah --plaintext fileb://blah --output text --query CiphertextBlob | base64 --decode > blah.enc
aws kms decrypt --ciphertext-blob fileb://blah.enc --output text --query Plaintext | base64 --decode

For base64 encrypted output:

aws kms encrypt --region ap-southeast-2 --key-id alias/blah --plaintext fileb://blah --output text --query CiphertextBlob > blah.enc
aws kms decrypt --ciphertext-blob fileb://<(cat blah.enc | base64 --decode) --output text --query Plaintext | base64 --decode

or try:
https://github.com/realestate-com-au/shush