I have a Splunk search string and I want to run this in every 25 hours.
Interesting question. I'm not sure that you can with Splunk's cron notation. If the search doesn't consume many resources, just run it every hour. Otherwise I suppose you could:
Check out http://stackoverflow.com/questions/1417098/cronjob-every-25-hours
I'm curious: what use case do you have for this search?