Gnucap - the Gnu Circuit Analysis Package

http://geda.seul.org/tools/gnucap/index.html

Gnucap is a general purpose circuit simulator. It performs nonlinear dc and
transient analyses, fourier analysis, and ac analysis. It can also be run in
batch mode or as a server. Spice compatible models for the MOSFET (level 1-7),
BJT, and diode are included in this release.