I am extracting netlist using magic. The .option scale = 5000u line is getting ignored in netgen. So there are parametric errors. How to get .option scale = 1 or some other workaround ? Also is there any way 2 extract only devices not any parasitics ? I tried extract no capacitance but it didn't generated .ext file.

Run ext2spice lvs first

@shbo (@Matt Venn): "ext2spice lvs" takes care of the .option scale issue and also takes care of the parasitic capacitances. "extract no capacitance" is an option setting---you need to do that, and then run "extract all" again. However, extraction is a two-part process (extract, then ext2spice) and it is better to let the "extract" part go ahead and do everything, and then use "ext2spice" to filter out the parasitics (or not). "ext2spice cthresh <threshold>" is what controls what parasitic caps get output. "ext2spice cthresh infinite" suppresses them all.

Thanks @Matt Venn and @Tim Edwards. Problems solved after following your directions.