Maildrop reads a mail message from standard input, then delivers the message to your mailbox. maildrop will optionally read instructions from a file, which describes how to filter incoming mail. Instructions can be provided having mail delivered to al...
Fetchmail is a free, full-featured, robust, well-documented remote-mail retrieval and forwarding utility intended to be used over on-demand TCP/IP links (such as SLIP or PPP connections).
Simple instructions for one variant of the vacation(1) program on Unix. (This doesn't appear to be the most standard version, but the general instructions look relatively ok.)