The affix ṇamul comes after the verb vid 'to know' and jīv 'to live' when the word yāvat is combined with them.,
As यावद्वेदं भुङ्क्ते 'he eats all that he gets'. यावज्जीवमधीते 'he studies as long as he lives, i.e. throughout his life'.,
यावति विन्द-जीवोः
Adhyāya 3 · Pāda 4 · Rule 30