you sure have something that will call a duration function, somewhere there you should have a difference betwen now and pretime that is the variable you look for (or create one if that is not set to a variable). If that is >12h (3600 * 12) or whatever you like, then BACKFILL
Now im not sure what your $timestamp looks like if its just unixtime but at the time of the pre then
set ago [expr $timestamp -[unixtime]] is all you need and youll be left with the amount of seconds between those two times.
if timestamp is more like a date format then use [clock scan $timestamp]
now youll need a limit set in seconds and then simply your if statement would look something like
set limit 3600
if {$ago > $limit} {
putqucik "PRIVMSG $chan :\[BACKFiLL] -- $rls was pred $ago ago
}
note 3600 = 1 hour in seconds hence the 12 * 3600 comment above i think
I think thats all correct anyway someone im sure will correct me if im wrong.
*edit*
ah looking at the above again it appears your $ago is more like 1 hour 30 secs ill assume your duration process does that if thats the case youll need to do that after the if cos the above code would work in seconds only. Hope this all helps not something I usually do this helping people business cos I suck at it lol