flasher - Copyright (C) 2002 Murray Nesbitt (websrc@nesbitt.ca)

    This program is protected and licensed under the following terms and
    conditions: 1) it may not be redistributed in binary form without the
    explicit permission of the author; 2) when redistributed in source
    form, in whole or in part, this complete copyright statement must
    remain intact.

    flasher monitors changes to one or more files, and indicates the
    number of writes to these files by briefly flashing a console LED
    once for each write.  The flashing sequence is repeated, after
    a brief pause, until the files have been read.  As the files are
    subsequently read, the number of LED flashes is reduced.  When all
    monitored files have been read, the console LED will be disabled.

    The most obvious use is to monitor specific system log or mail files.

    Multiple LEDs can be used. Each possible LED (-c, -n or -s) takes a
    list of colon-separated file arguments.  For example, when invoked as:

        # ./flasher -s /var/log/messages:/var/mail/root

    the Scroll Lock LED will flash once for each write made to either
    of these files, until the files are read.  When /var/log/messages
    has been read, the Scroll Lock LED will continue to flash once for
    each write that has been made to /var/mail/root, until it also has
    been read.

    The list of files can include files that don't yet exist.

    See the manual pages for more information.

    The program was designed without arbitrary limits of any kind (#
    of files it can handle, etc.).  Some of the behaviour (e.g. flash
    characteristics) can be modified--see "flasher.h" for details.

    Supported platforms:
        o FreeBSD
        o Linux
        o Solaris
        o SCO Unix was supported at one time, but is currently untested.
          Feedback is welcome!

    Support for other operating systems should require only minimal
    changes to "flasher.h".  One final note: 'gcc' is the assumed compiler
    on all platforms.