I use this in all the various little bash scripts I have running via timers. I love curl.

  local email_body=$(cat <<- PANCAKE
 From: ${SMTP_FROM}
 To: ${SMTP_TO}
 Subject: BACKUP SCRIPT FAILED

 $0 backup script failed on ${HOSTNAME}
 Exit code: ${exit_code}
 Failed at line: ${line_number}

 $(journalctl -o cat --user _SYSTEMD_INVOCATION_ID=${invocation_id} || true)
 PANCAKE
  )
  ## TODO: see above

  # Send email via authenticated SMTP using curl
  echo "${email_body}" | curl -s --url "${SMTP_URL}" \
    --ssl-reqd \
    --mail-from "${SMTP_FROM}" \
    --mail-rcpt "${SMTP_TO}" \
    --user "${SMTP_USERNAME}:${SMTP_PASSWORD}" \
    --upload-file -
  }

Interesting and good to be aware of

When on a random CLI though my personal preference though is still to use telnet as the commands are easily memorized and there’s something more natural about typing the email out and then sending it.