netbiff is a mail notification utility, like the traditional
xbiff, but designed to handle multiple mailboxes. It can provide
a graphical interface and/or execute shell commands when new
mail is received.

netbiff is the main interface program. It reads a configuration
and communicates with several backend mail checkers. It uses
either GTK or a terminal to display messages to the user.

netbiffd-imap checks for mail on an IMAP connection. It supports
checking multiple folders, and can connect using TCP, SSL,
or an SSH tunnel.

netbiffd-file checks for updates to a specific file using its
mtime field. The behavior is identical to the original xbiff.