I have had success using the NUT USB driver 'newhidup' under RedHat ES
4 but I do not know where the UPS shutdown command should be located.
The current placement of 'upsdrvctl shutdown' in '/etc/init.d/halt'
appears to be too late since the OS can't find the UPS at that point.
I can perform a shutdown at the command prompt using 'upsdrvctl
shutdown'. Any suggestions?