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 which comunicates with several mail checkers. It can use GTK or a terminal to display messages to 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.