The operation of both ngutmeg and ngspice may be affected by setting variables with the set command (17.5.63). In addition to the variables mentioned below, the set command also affects the behavior of the simulator via the options previously described under the section on .OPTIONS (15.1). You also may define new variables or alter existing variables inside .control ... .endc for later use in a user-defined script (see Chapt. 17.8).

The following list is in alphabetical order. All of these variables are acknowledged by ngspice. Frontend variables (e.g. on circuits and simulation) are not defined in ngnutmeg. The predefined variables that may be set or altered by the set command are:

• appendwrite
  Append to the file when a write command is issued, if one already exists.
• askquit
  Check to make sure that there are circuits suspended or plots unsaved. ngspice warns the user when he tries to quit if this is the case.brief If set to FALSE, the netlist will be printed.
• batchmode
  Set by ngspice if run with the -b command line parameter. May be used in input files to suppress plotting if ngspice runs in batch mode.
• colorN
  These variables determine the colors used, if X is being run on a color display. N may be between 0 and 15. Color 0 is the background, color 1 is the grid and text color, and colors 2 through 15 are used in order for vectors plotted. The value of the color variables should be names of colors, which may be found in the file /usr/lib/rgb.txt. ngspice for Windows does support only white background (color0=”white” with black grid and text) or or color0=”black” with white grid and text. Colors of its graph traces are set automatically.
• controlswait
  (only available with shared ngspice, chapt. 19.4.1.4) If the simulation is started with the background thread (command bg_run), the .control section commands are executed immediately after bg_run has been given, i.e. typically before the simulation has finished. This often is not very useful because you want to evaluate the simulation results. If controlswait is set in .spiceinit or spice.rc, the command execution is delayed until the background thread has returned (aka the simulation has finished). If set controlswait is given inside of the .control section, only the commands following this statement are delayed.
• cpdebug
  Print control debugging information.
• curplot
  (read only) Returns <type><no.> of the current plot. Type is one of tran, ac, op, sp, dc, unknown, no. is a number, sequentially set internally. This information is used to uniquely identify each plot.
• curplotdate
  Sets the date of the current plot.
• curplotname
  Sets the name of the current plot.
• curplottitle
  Sets the title (a short description) of the current plot.
• debug
  If set then a lot of debugging information is printed.
• device
  The name (/dev/tty??) of the graphics device. If this variable isn't set then the user's terminal is used. To do plotting on another monitor you probably have to set both the device and term variables. (If device is set to the name of a file, nutmeg dumps the graphics control codes into this file – this is useful for saving plots.)
• diff_abstol
  The relative tolerance used by the diff command (default is 1e-12).
• diff_reltol
  The relative tolerance used by the diff command (default is 0.001).
• diff_vntol
  The absolute tolerance for voltage type vectors used by the diff command (default is 1e-6).
• echo
  Print out each command before it is executed.
• editor
  The editor to use for the edit command.
• filetype
  This can be either ascii or binary, and determines the format of the raw file (compact binary or text editor readable ascii). The default is binary.
• fourgridsize
  How many points to use for interpolating into when doing Fourier analysis.
• gridsize
  If this variable is set to an integer, this number is used as the number of equally spaced points to use for the Y axis when plotting. Otherwise the current scale is used (which may not have equally spaced points). If the current scale isn't strictly monotonic, then this option has no effect.
• gridstyle
  Sets the grid during plotting with the plot command. Will be overridden by direct entry of gridstyle in the plot command. A linear grid is standard for both x and y axis. Allowed values are lingrid loglog xlog ylog smith smithgrid polar nogrid.
• hcopydev
  If this is set, when the hardcopy command is run the resulting file is automatically printed on the printer named hcopydev with the command lpr -Phcopydev -g file.
• hcopyfont
  This variable specifies the font name for hardcopy output plots. The value is device dependent.
• hcopyfontsize
  This is a scaling factor for the font used in hardcopy plots.
• hcopydevtype
  This variable specifies the type of the printer output to use in the hardcopy command. If hcopydevtype is not set, Postscript format is assumed. plot (5) is recognized as an alternative output format. When used in conjunction with hcopydev, hcopydevtype should specify a format supported by the printer.
• hcopyscale
  This is a scaling factor for the font used in hardcopy plots (between 0 and 10).
• hcopywidth
  Sets width of the hardcopy plot.
• hcopyheight
  Sets height of the hardcopy plot.
• hcopypscolor
  Sets the color of the hardcopy output. If not set, black & white plotting is assumed with different linestyles for each output vector. A valid color integer value yields a colored plot background (0: black 1: white, others see below). and colored solid lines. This is valid for Postscript only.
• hcopypstxcolor
  This variable sets the color of the text in the Postscript hardcopy output. If not set, black on white background is assumed, else it will be white on black background. Valid colors are 0: black 1: white 2: red 3: blue 4: orange 5: green 6: pink 7: brown 8: khaki 9: plum 10: orchid 11: violet 12: maroon 13: turquoise 14: sienna 15: coral 16: cyan 17: magenta 18: gray (for smith grid) 19: gray (for smith grid) 20: gray (for normal grid).
• height
  The length of the page for asciiplot and print col.
• history
  The number of events to save in the history list.
• inputdir
  The directory path of the last input file. It may be used to direct outputs into a directory relative to the input (even the into the same directory) by e.g. the command write $inputdir/outfile.raw vec1 vec2.
• interactive
  If interactive is set, numparam error handling may be done manually with user input from the console. If not, ngspice will exit upon a numparam error.
• lprplot5
  This is a printf(3s) style format string used to specify the command to use for sending plot(5)-style plots to a printer or plotter. The first parameter supplied is the printer name, the second parameter is a file name containing the plot. Both parameters are strings.
• lprps
  This is a printf(3s) style format string used to specify the command to use for sending Postscript plots to a printer or plotter. The first parameter supplied is the printer name, the second parameter is the file name containing the plot. Both parameters are strings.
• modelcard
  The name of the model card (normally .MODEL)
• moremode
  If moremode is set, whenever a large amount of data is being printed to the screen (e.g, the print or asciiplot commands), the output is stopped every screenful and continues when a carriage return is typed. If moremode is unset, then data scrolls off the screen without pausing.
• nfreqs
  The number of frequencies to compute in the Fourier command. (Defaults to 10.)
• ngbehavior
  Sets the compatibility mode of ngspice. Default value is 'all'. To be set in spinit (16.5) or .spiceinit (16.6). A value of 'all' improves compatibility with commercial simulators. Full compatibility is however not the intention of ngspice! The values 'ps', 'hs' and 'spice3' are available. See Chapt. 16.13.
• no_auto_gnd
  Setting this boolean variable by set no_auto_gnd in spinit or .spiceinit, ngspice will refrain from replacing all nodes named gnd by node 0. In using this setting, you will have to take care of proper zeroing appropriate ground nodes. If you failes to do so, ngspice may crash, or deliver wrong results.
• nobjthack
  BJTs can have either 3 or 4 nodes, which makes it difficult for the subcircuit expansion routines to decide what to rename. If the fourth parameter has been declared as a model name, then it is assumed that there are 3 nodes, otherwise it is considered a node. To disable this, you can set the variable nobjthack and force BJTs to have 4 nodes (for the purposes of subcircuit expansion, at least).
• nobreak
  Don't have asciiplot and print col break between pages.
• noasciiplotvalue
  Don't print the first vector plotted to the left when doing an asciiplot.
• nobjthack
  Assume that BJTs have 4 nodes.
• noclobber
  Don't overwrite existing files when doing IO redirection.
• noglob
  Don't expand the global characters `*', `?', `[', and `]'. This is the default.
• nonomatch
  If noglob is unset and a global expression cannot be matched, use the global characters literally instead of complaining.
• noparse
  Don't attempt to parse input files when they are read in (useful for debugging). Of course, they cannot be run if they are not parsed.
• noprintscale
  Don't print the scale in the leftmost column when a print col command is given.
• nosort
  Don't let display sort the variable names.
• nosubckt
  Don't expand subcircuits.
• notrnoise
  Switch off the transient noise sources (Chapt. 4.1.7).
• numdgt
  The number of digits to use when printing tables of data (print col). The default precision is 6 digits. On the VAX, approximately 16 decimal digits are available using double precision, so p should not be more than 16. If the number is negative, one fewer digit is printed to ensure constant widths in tables.
• num_threads
  The number of of threads to be used if OpenMP (see Chapt. 16.10) is selected. The default value is 2.
• plotstyle
  This should be one of linplot, combplot, or pointplot. linplot, the default, causes points to be plotted as parts of connected lines. combplot causes a comb plot to be done. It plots vectors by drawing a vertical line from each point to the X-axis, as opposed to joining the points. pointplot causes each point to be plotted separately.
• pointchars
  Set a string as a list of characters to be used as points in a point plot. Standard is `ox*+#abcdefhgijklmnpqrstuvwyz'. Some characters are forbidden.
• polydegree
  The degree of the polynomial that the plot command should fit to the data. If polydegree is N, then nutmeg fits a degree N polynomial to every set of N points and draws 10 intermediate points in between each end point. If the points aren't monotonic, then nutmeg tries to rotate the curve and reduce the degree until a fit is achieved.
• polysteps
  The number of points to interpolate between every pair of points available when doing curve fitting. The default is 10.
• program
  The name of the current program (argv[0]).
• prompt
  The prompt, with the character `!' replaced by the current event number. Single quotes ' ' are required around the specified string unless you really want it expanded.
• rawfile
  The default name for created rawfiles.
• remote_shell
  Overrides the name used for generating rspice runs (default is rsh).
• renumber
  Renumber input lines when an input file has .includes.
• rndseed
  Seed value for random number generator (used by sgauss, sunif, and rnd functions). It is set by the option command 'option seed=val|random'.
• rhost
  The machine to use for remote ngspice runs, instead of the default one (see the description of the rspice command, below).
• rprogram
  The name of the remote program to use in the rspice command.
• sharedmode
  Variable is set when ngspice runs in its shared mode (from ngspice.dll or ngspice_xx.so). May be used in universal input files to suppress plotting because a graphics interface is lacking.
• sim_status
  will bet set to 0 when the simulation starts. If there is an error and the simulation fails with 'xx simulation(s) aborted', then sim_status is set to 1. The variable can be used in scripted loops within a transient simulation to allow special handling e.g. in case of non-convergence.
• sourcepath
  A list of the directories to search when a source command is given. The default is the current directory and the standard ngspice library (/usr/local/lib/ngspice, or whatever LIBPATH is #defined to in the ngspice source). The command
  set sourcepath = ( e:/ D:/ . c:/spice/examples )
  will overwrite the default. The search sequence now is: current directory, e:/, d:/, current directory (again due to .), c:/spice/examples. 'Current directory' is depending on the OS.
• specwindow
  Windowing for commands spec **** (17.5.76) or** fft (17.5.27). May be one of the following: bartlet blackman cosine gaussian hamming hanning none rectangular triangle. **fft.
• spicepath
  The program to use for the aspice command. The default is /cad/bin/spice.
• sqrnoise
  If set, noise data outputs will be given as (V^{2}/Hz) or (A^{2}/Hz), otherwise as the usual (V/\left. \sqrt{}Hz \right.) or (A/\left. \sqrt{}Hz \right.).
• strict_errorhandling
  If set by the user, an error detected during circuit parsing will immediately lead ngspice to exit with exit code 1 (see 18.5). May be set in files spinit (16.5) or .spiceinit (16.6) only.
• subend
  The card to end subcircuits (normally .ends).
• subinvoke
  The prefix to invoke subcircuits (normally X).
• substart
  The card to begin subcircuits (normally .subckt).
• term
  The mfb name of the current terminal.
• ticmarks
  An integer value n, n tics (a small 'x') will be set on your graph.
• ticlist
  A list of integers, e.g. ( 4 14 24 ) to set tics (small 'x') on your graph.
• units
  If this is degrees, then all the trig functions will use degrees instead of radians.
• unixcom
  If a command isn't defined, try to execute it as a UNIX command. Setting this option has the effect of giving a rehash command, below. This is useful for people who want to use ngnutmeg as a login shell.
• wfont
  Set the font for the graphics plot in MS Windows. Typical fonts are courier, times, arial and all others found on your machine. Default is courier.
• wfont_size
  The size of the windows font. The default depends on system settings.
• width
  The width of the page for asciiplot and print col (see also 15.6.7).
• win_console
  is set when ngspice runs in a console under Windows.
• x11lineararcs
  Some X11 implementations have poor arc drawing. If you set this option, ngspice will plot using an approximation to the curve using straight lines.
• xbrushwidth
  Linewidth for grid, border and graph.
• xfont
  Set the font for the graphics plot in X11 (Linux, Cygwin, etc.). Input format still has to be checked.
• xtrtol
  Set trtol, e.g. to 7, to avoid the default speed reduction (accuracy increase) for XSPICE (see 16.9). Be aware of potential precision degradation or convergence issues using this option.