Peter Seebach writes:
> Proposed cool feature, found in BSD/OS:
> 
> On the way up, the system diffs dmesg.boot with the "current" dmesg
> output, right before storing the new dmesg.boot.
> 
> This is a feature I often miss when playing with configurations.

I posted something like this a few years back.  Didn't get a lot of
interest. :(

Here is what I have been using.
#!/bin/sh
#
# check for changes in the hardware configuration
#
if [ -f /var/log/dmesglog ]; then
        echo -n 'checking hardware config:'
        mv /var/log/dmesglog /var/log/dmesglog.0
        dmesg | sed -n '/^NetBSD/h; /^NetBSD/!H; ${ x; p; q; }' \
                > /var/log/dmesglog
        diff -bc /var/log/dmesglog.0 /var/log/dmesglog > /tmp/diff.$$
        if [ -s /tmp/diff.$$ ]; then
                cat /tmp/diff.$$ | Mail -s "hardware change" root
                echo ' changed.'
        else
                echo ' no change.'
        fi
        rm -f /tmp/diff.$$
fi

#
# end-of-file
#

-Andrew
-- 
-----------------------------------------------------------------
Andrew Gillham                            | NetBSD ist Affengeil.
gillham@whirlpool.com                     | Nachts ist es kaelter
I speak for myself, not for my employer.  | als draussen.