Agni Purāṇa

160 - Duties of a brahmin leading life in the forest

Pushkara said: 

1-2. Listen to me! Ishall describe the duties of an anchorite leading life in the forest. Heshould have matted hair, worship fire, sleep on the ground and wear the hide of an antelope. Heshould live in the forest. Heshould maintain his life with milk, roots, nivara (rice growing uncultivated) and fruits. Heshould not take alms. Heshould bathe thrice a day. Heshould observe celibacy. 

3. The duty of an anchorite is to worship gods and guests. A householder after having seen the grandchildshould resort to the forest. 

4-5. The third part of one's life (should be spent in the forest) either alone or with the wife. Oneshould do severe penance in the midst of five fires in the summer, under the clouds as theshelter in the rainy season, with wet dress in the winter. Oneshould resort to a life of not expecting (any thing from anybody) and go on straight in (different) directions.