The following commands .print (15.6.2), .plot (15.6.3) and .four (15.6.4) are valid only if ngspice is started in batch mode (see 16.4.1), whereas .save and the equivalent .probe are aknowledged in all operating modes.

If you start ngspice in batch mode using the -b command line option, the outputs of .print, .plot, and .four are printed to the console output. You may use the output redirection of your shell to direct this printout into a file (not available with MS Windows GUI). As an alternative you may extend the ngspice command by specifying an output file:

ngspice -b -o output.log input.cir

If you however add the command line option -r to create a rawfile, .print and .plot are ignored. If you want to involve the graphics plot output of ngspice, use the control mode (16.4.3) instead of the -b batch mode option.