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.)
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).