How can we run clear automatic accounting by T:code F.13 but in ?the background

Automatic clearing is done through Tcode F.13....Here in this transaction you will give the account and process ,the documnets will be cleared based on the Criteria you have given in Configuration for clearing the account.

Path for configuration of clearing account.

Easy access-FA-GLA-BT-OICLEARING-PREPARE AUTOMATIC CLEARING.

Here you have to give atleast1 criteria for clearing the account,basis on which when you run the Tcode F.13 it will clear the account.