#!/bin/sh

dmesg | perl -ne ' 
   ($dev) = /^(\w+\d):? /; 
   ($irq) = / irq (\d\d?)/; 
   push( @{ $irq[$irq] }, $dev);

END {
   foreach $irq ( 1..$#irq ) { 
      @dev = @{ $irq[$irq] };
      print "IRQ $irq is ", (@dev) ? "used by @dev" : "available";
      print " *** POTENTIAL CONFLICT ***" if (@dev > 1);
      print "\n";
   }
}'