gmail-send

gmail send    --to <addr> --subject <s> --body-file <file> [--cc][--bcc][--attach][--dry-run]
gmail reply   <message-id> --body-file <file> [--all] [--attach] [--dry-run]
gmail forward <message-id> --to <addr> [--body-file <file>] [--no-attachments] [--dry-run]

--to, --cc, --bcc, and --attach all repeat. --json gives the Envelope.

The rule for this session

Preview, show, confirm, send. In that order, every time.