24.3.3.7. Special Options
These options are occasionally useful for overriding defaults often found in the .fetchmailrc file.
-a — Fetchmail downloads all messages from the remote email server, whether new or previously viewed. By default, Fetchmail only downloads new messages.
-k — Fetchmail leaves the messages on the remote email server after downloading them. This option overrides the default behavior of deleting messages after downloading them.
-l — Fetchmail does not download any messages over a particular size and leaves them on the remote email server.
<max-number-bytes>
--quit — Quits the Fetchmail daemon process.
More commands and .fetchmailrc options can be found in the fetchmail man page.