It is not outlook-dependent. By default, mails are interpreted as text. If you want to send a HTML mail, you should inform the mail reader to handle it as html. It can be done with the Content-type: text/html
SMTP header, just as in HTTP.
An example mail header which should work:
From: <adam@example.org>
To: <eva@example.org>
Subject: Test
Content-type: text/plain; charset=iso-8859-15
Content-Transfer-Encoding: 8bit
<html><b>test</b></html>
Your mail program is probably a part of your mailing system, but probably it would work if you simple gave this header to the beginning of your mail body. So:
you$ mail -s eva@example.com
Content-type: text/html
<html><b>test</b></html>
If not, most mail softwares contain a tool named sendmail
, which is capable to do that.
There are various libraries / modules in every scripting language common in linux, which can create more complex mails as well (attached files, inline images, dual textonly and html content, etc).