Using curl to send email

curl --ssl-reqd \
  --url 'smtps://smtp.gmail.com:465' \
  --user 'username@gmail.com:password' \
  --mail-from 'username@gmail.com' \
  --mail-rcpt 'john@example.com' \
  --upload-file mail.txt

mail.txt file contents:

From: "User Name" <username@gmail.com>
To: "John Smith" <john@example.com>
Subject: This is a test

Hi John,
I’m sending this mail with curl thru my gmail account.
Bye!

Additional info:

1. I’m using curl version 7.21.6 with SSL support.

2. You don’t need to use the --insecure switch, which prevents curl from performing SSL connection verification. See this online resource for further details.

3. It’s considered a bad security practice to pass account credentials thru
   command line arguments. Use --netrc-file. See the documentation.

4. You must turn on access for less secure apps or the newer App passwords.