A Sadhu is also known as yogi or Sanyasi. He is a Hindu ascetic and equivalent to Faquir of Sufism in Islam. Sadhu is in fact a Hindu ascetic who has renounced all the social activity, authorities the materialistic things and money in order to quest for the truth of life. Many times people don't find the difference among a guru, a priest and a Sadhu. A Sadhu is a guru or a priest for them. But they do not confused with guru or priest as Sadhu. A Sadhu is too far from the orthodox priesthood because he renounces everything which is considered superior to the rituals of the priests.
The concept of the Sadhu is connected with the early images of Shiva himself with his matted hair and body besmears with ashes.
Normally a Sadhu wears a kind of robe in saffron color.The saffron color is very important because like other colors it also has specific vibrations. This is the color of the sun and fire and gold which symbolizes purity,energy and gold, it also represents religious abstinence. It is the color of holy men and ascetic who have renounced the world. Wearing this color means the quest for life. Traditionally they carry a long musical instrument called tong, a trident, a kamandal (a wooden or brass waterpot), which they use to carry water and to collect alms.
They wear a rosary around their neck of the Rudraksh a bead, which comes from the tree of ELAEOCARPUS GANITRUS, found in the Himalayas and is very effective for the blood pressure to bring it to normal. They have matted hair and never cut hair besmeares with the ash all over their body like Shiva, sometimes they live in nude or wrap out a hide of an animal. Generally a sadhu puts some temporary marks on his hands chests neck and on forehead, which is made off sandal wood paste or ash. There can be endless variation of this sectarian mark depending on the sect.
There are two sects of the Sadhus:-
The Shaivite Sadhus
The Vaishnavite Sadhus
The Shaivite Sadhus: are the Shiva's followers and then they are divided into various sub-sects. The Dasanami sect (or the monks with 10 names) has about 10 branches and they are scattered all over India. They each have their own kind of army called the Nagas and they follow tantrism and shaktism.They eat meat take stimulants such as hash,cannabis and are often criticized or their erotic practicesThe Gorakhnathis sect wears large earrings. The aghoris are notorious for their rites involving the deads.They generally live in crematorium and besmears the ash of crematorium. Then there is lingayats sect who worship on ling (phallus) as the symbol of shiva
The Vaishnavite Sadhus: the sadhus of this sect is devoted to Vishnu.This sect was developed much later than the shivaits. They are commonly called vairagies (the detached ones) they are more calm sadhus than the shivaits. They are the members of various schools of bakthi (devotion) Their common identifying marks on their fore head is a big ( U ) and then there is a dot ( . ) inside the U. or there is an ( I ) inside the U. They normally wear white clothes and carry the rosary of Tulsi (sacred basil).Unlike the common Hindu who is cremated, the sadhu is buried usually in the sitting position and the burial site normally becomes a place of worship.