The Army Act,1950
Section 169. Execution of sentence of imprisonment
(1) Whenever any sentence of imprisonment is passed under this Act by a court- martial or whenever any sentence of death or transportation is commuted to imprisonment, the confirming officer or in case of a summary court- martial the officer holding the Court or such other officer as may be prescribed, shall, save as otherwise provided in sub- sections (3) and (4), direct either that the sentence shall be carried out by confinement in a military prison or that it shall be carried out by confinement in a civil prison.
(2) When a direction has been made under sub- section (1) the commanding officer of the person under sentence or such other officer as may be prescribed shall forward a warrant in the prescribed form to the officer in charge of the prison in which such person is to be confined and shall arrange for his despatch to such prison with the warrant.
(3) In the case of a sentence of imprisonment for a period not exceeding three months and passed under this Act by a court- martial, the appropriate officer under sub- section (1) may direct that the sentence shall be carried out by confinement in military custody instead of in a civil or military prison.
(4) On active service, a sentence of imprisonment may be carried out by confinement in such place as the officer commanding the forces in the field may from time to time appoint.
Period of custody undergone by the officer of person to be set off against the imprisonment.