On Sun, Sep 18, 2022 at 09:27:46AM +0200, Yvan Masson wrote: > So the `mailutils` package with `mail` command is optional: `sendmail` could > be used directly in scripts (but it might be a bit less practical to use, > see for example https://www.computerhope.com/unix/usendmai.htm#examples).
If you call /usr/sbin/sendmail, you have to write all of the headers yourself, with correct (or at least acceptably close) syntax. The only time a shell script should be calling /usr/sbin/sendmail directly is when you're trying to do something that your MUA (mailx, et al.) doesn't allow, such as forging a bogus Date: header, or overriding the envelope sender address. In normal usage, scripts should always be calling mailx or an equivalent program which is *designed* to create the e-mail headers correctly. This is especially true if you're sending attachments. Writing the MIME headers and attachment markup yourself is not going to be fun.
