Writ

A writ is a formal written order issued by a body with administrative or judicial jurisdiction
http://en.wikipedia.org/wiki/Writ
Prerogative writs
The "prerogative" writs are a subset of the class of writs, those that are to be heard ahead of any other cases on a court's docket except other such writs. The most common of the other such prerogative writs are habeas corpus, quo warranto, prohibito, mandamus, procedendo, and certiorari.

The due process for petitions for such writs is not simply civil or criminal, because they incorporate the presumption of nonauthority, so that the official who is the respondent has the burden to prove his authority to do or not do something, failing which the court has no discretion but to decide for the petitioner, who may be any person, not just an interested party. In this they differ from a motion in a civil process in which the burden of proof is on the movant, and in which there can be a question of standing.

Indian law

Under the Indian legal system, jurisdiction to issue 'prerogative writs' is given to the Supreme Court, and to the High Courts of Judicature of all Indian states. Parts of the law relating to writs are set forth in the Constitution of India. The Supreme Court, the highest in the country, may issue writs under Article 32 of the Constitution for enforcement of Fundamental Rights and under Articles 139 for enforcement of rights other than Fundamental Rights, while High Courts, the superior courts of the States, may issue writs under Articles 226. 'Writ' is eminently designed by the makers of the Constitution, and in the same way it is developed very widely and efficiently by the courts in India. The Constitution broadly provides for five kinds of "prerogative" writs, namely, Habeas Corpus, Certiorari, Mandamus, Quo Warranto and Prohibition. Basic details of which are as follows:
The writ of prohibition is issued by a higher court to a lower court prohibiting it from taking up a case because it falls outside the jurisdiction of the lower court. Thus, the higher court transfers the case to itself.

The writ of habeas corpus is issued to a detaining authority, ordering the detainer to produce the detained person in the issuing court, along with the cause of his or her detention. If the detention is found to be illegal, the court issues an order to set the person free.

The writ of certiorari is issued to a lower court directing that the record of a case be sent up for review, together with all supporting files, evidence and documents, usually with the intention of overruling the judgement of the lower court. It is one of the mechanisms by which the fundamental rights of the citizens are upheld.

The writ of mandamus is issued to a subordinate court, an officer of government, or a corporation or other institution commanding the performance of certain acts or duties.

The writ of quo warranto is issued against a person who claims or usurps a public office. Through this writ the court inquires 'by what authority' the person supports his or her claim.
[edit]Other writs

A writ of attachment permits the arrest of a person or the seizure of private property.
A writ of capias directs an officer to take into custody the person named in the writ or order[1]
A writ of coram nobis corrects a previous error "of the most fundamental character" to "achieve justice" where "no other remedy" is available, e.g., when a judgment was rendered without full knowledge of the facts.
A writ of elegit orders the seizure of a portion of a debtor's lands and all his goods (except work animals) towards satisfying a creditor, until the debt is paid off.
A writ of error is issued by an appellate court, and directs a lower court of record to submit its record of the case laid for appeal.
A writ of exigent (or exigend) commands a sheriff to summon a defendant indicted for a felony, who had failed to appear in court, to deliver himself up upon pain of outlawry or forfeiture of his goods.
A writ of fieri facias (a/k/a "fi fa") commands a sheriff to take and auction off enough property from a losing party to pay the debt (plus interest and costs) owed by a judgment debtor.
A writ of mittimus orders either (1) a court to send its record to another or a jailor to receive the accused in his or her custody at any point during the investigative or trial process.
A writ of ne exeat republica (a/k/a "writ of ne exeat") restrains defendant who attempts to flee the country where he or she is being tried.
A writ of praemunire instructs a sheriff to order someone to appear in court to answer for any of a number of different crimes.
A writ of frrts contains a command to stay the proceedings at law.
A writ of venire facias summons jurors to appear in court.