$ EDITOR='cat' rails credentials:edit
Editing config/credentials.yml.enc...
# aws:
#   access_key_id: 123
#   secret_access_key: 345

# Used as the base secret for all MessageVerifiers in Rails, including the one protecting cookies.
secret_key_base: [...]
File encrypted and saved.

$ EDITOR='echo "foo: bar" >>' rails credentials:edit
Editing config/credentials.yml.enc...
foo: bar >> /tmp/20240111-42-h8cs8b-credentials.yml
File encrypted and saved.

$ EDITOR='cat' rails credentials:edit
Editing config/credentials.yml.enc...
# aws:
#   access_key_id: 123
#   secret_access_key: 345

# Used as the base secret for all MessageVerifiers in Rails, including the one protecting cookies.
secret_key_base: [...]
File encrypted and saved.