Bhashya
स यावदादित्य पुरस्तादुदेता पश्चादस्तमेता द्विस्तावत्ततो द्विगुण काल दक्षिणत उदेता उत्तरतोऽस्तमेता रुद्राणातावद्भोगकाल ॥
In plain words
For as long as the sun rises in the east and sets in the west, and for twice that duration plus an additional twofold period rises in the south and sets in the north—that is the full span of enjoyment for the Rudras.
Close to the Sanskrit
As long as the sun rises in the east and sets in the west, twice that much plus a twofold time period it rises in the south and sets in the north: that is the duration of enjoyment of the Rudras.