If file names are given on the command line, gnuplot loads each file with the load command, in the order specified, and exits after the last file is processed. If no files are given, gnuplot prompts for interactive commands.
Here are some of its features:
Plots any number of functions, built up of C operators, C library functions, and some things C doesn't have like **, sgn(), etc.
User-defined constants and functions.
All computations performed in the complex domain. Just the real part is plotted by default, but functions like imag() and abs() and arg() are available to override this.
Also support for plotting data files, to compare actual data to theoretical curves.
Nonlinear least-squares fitting.
2D plots with mouse-controlled zooming.
3D plots with mouse-controlled point of view.
User-defined X and Y ranges (optional auto-ranging), smart axes scaling, smart tic marks.
Labelling of X and Y axes.
Shell escapes and command line substitution.
Load and save capability.
Support for many output devices and file formats.
-p, --persist lets plot windows survive after main gnuplot program exits.
-e "command list" executes the requested commands before loading the next input file.
-h, --help print summary of usage
-V show current version
-clear requests that the window be cleared momentarily before a new plot is displayed.
-gray requests grayscale rendering on grayscale or color displays. (Grayscale displays receive monochrome rendering by default.)
-mono forces monochrome rendering on color displays.
-raise raises the plot window after each plot.
-noraise does not raise the plot window after each plot.
-tvtwm requests that geometry specifications for position of the window be made relative to the currently displayed portion of the virtual root.
These options may also be controlled with resources in your .Xdefaults file. For example: gnuplot*gray: on .
Gnuplot provides a command line option (-pointsize v) and a resource (gnuplot*pointsize: v) to control the size of points plotted with the "points" plotting style. The value v is a real number (greater than 0 and less than or equal to ten) used as a scaling factor for point sizes. For example, -pointsize 2 uses points twice the default size, and -pointsize 0.5 uses points half the normal size.
For monochrome displays, gnuplot does not honor foreground or background colors. The default is black-on-white. -rv or gnuplot*reverseVideo: on requests white-on-black.
For color displays gnuplot honors the following resources (shown here with default values). The values may be color names in the X11 rgb.txt file on your system, hexadecimal RGB color specifications (see X11 documentation), or a color name followed by a comma and an intensity value from 0 to 1. For example, blue,.5 means a half intensity blue.
When -gray is selected, gnuplot honors the following resources for grayscale or color displays (shown here with default values). Note that the default background is black.
Gnuplot honors the following resources for setting the width in pixels of plot lines (shown here with default values.) 0 or 1 means a minimal width line of 1 pixel width. A value of 2 or 3 may improve the appearance of some plots.
Gnuplot honors the following resources for setting the dash style used for plotting lines. 0 means a solid line. A 2 digit number jk (j and k are >= 1 and <= 9) means a dashed line with a repeated pattern of j pixels on followed by k pixels off. For example, '16' is a "dotted" line with 1 pixel on followed by 6 pixels off. More elaborate on/off patterns can be specified with a 4 digit value. For example, '4441' is 4 on, 4 off, 4 on, 1 off. The default values shown below are for monochrome displays or monochrome rendering on color or grayscale displays. For color displays, the defaults for all are 0 (solid line) except for axisDashes which defaults to a '16' dotted line.
The size or aspect ratio of a plot may be changed by resizing the gnuplot window.
Additions for labelling by Russell Lang, Monash University, Australia.
Further additions by David Kotz, Dartmouth College, New Hampshire, USA (formerly of Duke University, North Carolina, USA).