Code:
echo -e "From: test@test.com\nSubject: this is the subject\nReply-to: reply@server.com\nHere goes the mail body" | mini_sendmail -fnotused@ -ssmtp.server.com recipient@testide.com
where -e option in echo interprets special \n character as a newline. The -f option in mini_sendmail does not seem to be used at all.