How to Run sendmail

One way to run sendmail is to provide it with the name of a recipient as the only command-line argument. For example, the following sends a mail message to george:

% /usr/lib/sendmail george

Multiple recipients can also be given. For example, the following sends a mail message to george, truman, and teddy:

% /usr/lib/sendmail george,truman,teddy

The sendmail program accepts two different kinds of command-line arguments. Arguments that do not begin with a - character (such as george) are assumed to be recipients. Arguments that do begin with a - character are taken as switches that determine the behavior of sendmail. The recipients must always follow all the switched arguments. Any switched arguments that follow recipients will be interpreted as recipient addresses, potentially causing bounced mail.

In this chapter, we will cover only a few of these switch-style command-line arguments (see Table 1-1). The complete list of command-line switches, along with an explanation of each, is presented in Chapter 6 on page 220.

Table 1-1. Some command-line switches




Set operating mode.


Run in verbose mode.


Run in debugging mode.

Become a mode (-b)

The sendmail program can function in a number of different ways depending on which form of -b argument you use. One form, for example, causes sendmail to display the contents of the queue. Another causes sendmail to rebuild the aliases database. A complete list of the -b command-line mode-setting switches ...

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