BIFF(1)                      General Commands Manual                     BIFF(1)

     biff – be notified if mail arrives and who it is from

     biff [n | y | b]

     The biff utility informs the system whether you want to be notified on your
     terminal when mail arrives.

     Affected is the first terminal associated with the standard input, standard
     output or standard error file descriptor, in that order.  Thus, it is
     possible to use the redirection facilities of a shell to toggle the
     notification for other terminals than the one biff runs on.

     The following options are available:

     n       Disable notification.

     y       Enable header notification.

     b       Enable bell notification.

     When header notification is enabled, the header and first few lines of the
     message will be printed on your terminal whenever mail arrives.  A “biff y”
     command is often included in the file .login or .profile to be executed at
     each login.

     When bell notification is enabled, only two bell characters (ASCII \007)
     will be printed on your terminal whenever mail arrives.

     If no arguments are given, biff displays the present notification status of
     the terminal to the standard output.

     The biff utility operates asynchronously.  For synchronous notification use
     the MAIL variable of sh(1) or the mail variable of csh(1).

     The biff utility exits with one of the following values:

     0       Notification is enabled.

     1       Notification is disabled.

     >1      An error occurred.

     Previous versions of the biff utility affected the terminal attached to
     standard error without first trying the standard input or output devices.

     csh(1), mail(1), sh(1), comsat(8)

     The biff command appeared in 4.0BSD.  It was named after the dog of Heidi
     Stettner.  He died in August 1993, at 15.

macOS 12.1                        July 9, 2002                        macOS 12.1