sendmail, 4th Edition

Run sendmail by Hand

Most users do not run sendmail directly. Instead, they use one of many MUAs to compose a mail message. Those programs invisibly pass the mail message to sendmail, creating the appearance of instantaneous transmission. The sendmail program then takes care of delivery in its own seemingly mysterious fashion.

Although most users don’t run sendmail directly, it is perfectly legal to do so. You, like many system managers, might need to do this to track down and solve mail problems.

Here’s a demonstration of one way to run sendmail by hand. First create a file named sendstuff with the following contents:

This is a one-line message.

Second, mail this file to yourself with the following command line, where you is your login name:

% /usr/sbin/sendmail you <sendstuff

Here, you run sendmail directly by specifying its full pathname.^[5] When you run sendmail, any command-line arguments that do not begin with a - character are considered to be the names of the people to whom you are sending the mail message.

The <sendstuff sequence causes the contents of the file that you have created (sendstuff) to be redirected into the sendmail program. The sendmail program treats everything it reads from its standard input (up to the end of the file) as the mail message to transmit.^[6]

Now view the mail message you just sent. How you do this will vary. Many users just type mail to view their mail. Others use the mh(1) package and type inc to receive and show to view their mail. No matter how ...