Let's take as an example the Four-Bit binary adder MOS circuit shown in Chapt. 21.6, stored in a file adder-mos.cir. You may start the simulation immediately by calling

ngspice -b -r adder.raw -o adder.log adder-mos.cir

ngspice will start, simulate according to the .tran command and store the output data in a rawfile adder.raw. Comments, warnings and infos go to log file adder.log. Commands for batch mode operation are described in Chapt. 15.