Cross platform
echo Z3JlZ0Bhc3NldG1hcHBpbmcuY29tCg== | perl -MMIME::Base64 -pe 's/(.+)/decode_base64($1)/e' echo Z3JlZ0Bhc3NldG1hcHBpbmcuY29tCg== | perl -MMIME::Base64 -pe 's/(.+)/decode_base64($1)/e' echo Z3JlZ0Bhc3NldG1hcHBpbmcuY29tCg== | docker run -i busybox base64 -d
>>> import base64
>>> email = "Z3JlZ0Bhc3NldG1hcHBpbmcuY29tCg=="
>>> print(base64.b64decode(email).decode('utf-8'))