# Introduction

Gnuplot is a portable command-line driven graphing utility for Linux, OS/2, MS Windows, OSX, VMS, and many other platforms. The source code is copyrighted but freely distributed (i.e., you don't have to pay for it). It was originally created to allow scientists and students to visualize mathematical functions and data interactively, but has grown to support many non-interactive uses such as web scripting. It is also used as a plotting engine by third-party applications like Octave. Gnuplot has been supported and under active development since 1986.

Gnuplot supports many types of plots in either 2D and 3D. It can draw using lines, points, boxes, contours, vector fields, surfaces, and various associated text. It also supports various specialized plot types.

Gnuplot supports many different types of output: interactive screen terminals (with mouse and hotkey input), direct output to pen plotters or modern printers, and output to many file formats (eps, emf, fig, jpeg, LaTeX, pdf, png, postscript, ...). Gnuplot is easily extensible to include new output modes. Recent additions include interactive terminals based on wxWidgets (usable on multiple platforms), and Qt. Mouseable plots embedded in web pages can be generated using the svg or HTML5 canvas terminal drivers.

The command language of gnuplot is case sensitive, i.e. commands and function names written in lowercase are not the same as those written in capitals. All command names may be abbreviated as long as the abbreviation is not ambiguous. Any number of commands may appear on a line, separated by semicolons (;). Strings may be set off by either single or double quotes, although there are some subtle differences. See syntax (p. ) and quotes (p. ) for more details. Example:

         set title "My First Plot";  plot 'data';  print "all done!"

Commands may extend over several input lines by ending each line but the last with a backslash (). The backslash must be the last character on each line. The effect is as if the backslash and newline were not there. That is, no white space is implied, nor is a comment terminated. Therefore, commenting out a continued line comments out the entire command (see comments (p. )). But note that if an error occurs somewhere on a multi-line command, the parser may not be able to locate precisely where the error is and in that case will not necessarily point to the correct line.

In this document, curly braces ({}) denote optional arguments and a vertical bar () separates mutually exclusive choices. Gnuplot keywords or help topics are indicated by backquotes or boldface (where available). Angle brackets () are used to mark replaceable tokens. In many cases, a default value of the token will be taken for optional arguments if the token is omitted, but these cases are not always denoted with braces around the angle brackets.

For built-in help on any topic, type help followed by the name of the topic or help ? to get a menu of available topics.

A large set of demo plots is available on the web page

http://www.gnuplot.info/demo/`http://www.gnuplot.info/demo/`

When run from command line, gnuplot is invoked using the syntax

         gnuplot {OPTIONS} file1 file2 ...

where file1, file2, etc. are input file as in the load command. On X11-based systems, you can use

         gnuplot {X11OPTIONS} {OPTIONS} file1 file2 ...

see your X11 documentation and x11 (p. ) in this document.

Options interpreted by gnuplot may come anywhere on the line. Files are executed in the order specified, as are commands supplied by the -e option, for example

         gnuplot   file1.in   -e "reset"   file2.in

The special filename `"`-`"` is used to force reading from stdin. Gnuplot exits after the last file is processed. If no load files are named, Gnuplot takes interactive input from stdin. See help batch/interactive (p. ) for more details. The options specific to gnuplot can be listed by typing

         gnuplot --help

See command line options (p. ) for more details.

In sessions with an interactive plot window you can hit 'h' anywhere on the plot for help about hotkeys and mousing features. Section seeking-assistance will help you to find further information, help and FAQ.