C Copyright (C) 1986 - 1993, 1998, 1999, 2000, 2001, 2004 Thomas Williams, Colin Kelley et al.

C

1 gnuplot

?gnuplot

^<h2 align="center"> An Interactive Plotting Program </h2>

^<p align="center"> Thomas Williams & Colin Kelley</p>

^<p align="center"> Version 5 organized by Ethan A Merritt and others</p>

^<p align="center">Major contributors (alphabetic order):<br>

^<br>

^ Hans-Bernhard Broeker, John Campbell,<br>

^ Robert Cunningham, David Denholm,<br>

^ Gershon Elber, Roger Fearick,<br>

^ Carsten Grammes, Lucas Hart,<br>

^ Lars Hecking, Péter Juhász,<br>

^ Thomas Koenig, David Kotz,<br>

^ Ed Kubaitis, Russell Lang,<br>

^ Timothée Lecomte, Alexander Lehmann,<br>

^ Alexander Mai, Bastian Märkisch,<br>

^ Ethan A Merritt, Petr Mikulík,<br>

^ Carsten Steger, Shigeharu Takeno,<br>

^ Tom Tkacik, Jos Van der Woude,<br>

^ James R. Van Zandt, Alex Woo, Johannes Zellner<br>

^</p>

^<p align="center"> Copyright (C) 1986 - 1993, 1998 - 2004 Thomas Williams, Colin Kelley<br>

^ Copyright (C) 2004 - 2018 various authors</p>

^<p align="center"> Mailing list for comments: <tt>[email protected]</tt><br>

^ Mailing list for bug reports: <tt>[email protected]</tt><br>

^ Web access (preferred): <tt>http://sourceforge.net/projects/gnuplot</tt></p>

^<p align="center"> This manual was originally prepared by Dick Crawford</p>

2 Copyright

?copyright

?license

Copyright (C) 1986 - 1993, 1998, 2004, 2007 Thomas Williams, Colin Kelley

Permission to use, copy, and distribute this software and its

documentation for any purpose with or without fee is hereby granted,

provided that the above copyright notice appear in all copies and

that both that copyright notice and this permission notice appear

in supporting documentation.

Permission to modify the software is granted, but not the right to

distribute the complete modified source code. Modifications are to

be distributed as patches to the released version. Permission to

distribute binaries produced by compiling modified sources is granted,

provided you

1. distribute the corresponding source modifications from the

released version in the form of a patch file along with the binaries,

2. add special version identification to distinguish your version

in addition to the base release version number,

3. provide your name and address as the primary contact for the

support of your modified version, and

4. retain our contact information in regard to use of the base software.

Permission to distribute the released version of the source code along

with corresponding source modifications in the form of a patch file is

granted with same provisions 2 through 4 for binary distributions.

This software is provided "as is" without express or implied warranty

to the extent permitted by applicable law.

AUTHORS

Original Software:

Thomas Williams, Colin Kelley.

Gnuplot 2.0 additions:

Russell Lang, Dave Kotz, John Campbell.

Gnuplot 3.0 additions:

Gershon Elber and many others.

Gnuplot 4.0 and 5.0 additions:

See list of contributors at head of this document.

2 Introduction

?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` and `quotes` 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`). 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

^ <a href="http://www.gnuplot.info/demo/">

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

^ </a>

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` 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` for more details.

The options specific to gnuplot can be listed by typing

gnuplot --help

See `command line options` 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.

2 Seeking-assistance

?help-desk

?faq

?FAQ

?seeking-assistance

The canonical gnuplot web page can be found at

^ <a href="http://www.gnuplot.info">

http://www.gnuplot.info

^ </a>

Before seeking help, please check file FAQ.pdf or the above website for

^ <a href="http://www.gnuplot.info/faq/">

FAQ (Frequently Asked Questions) list.

^ </a>

If you need help as a gnuplot user, please use the newsgroup

comp.graphics.apps.gnuplot

Instructions for subscribing to gnuplot mailing lists may be

found via the gnuplot development website on SourceForge

^ <a href="http://sourceforge.net/projects/gnuplot">

http://sourceforge.net/projects/gnuplot

^ </a>

Please note that before you write to any of the gnuplot mailing lists,

you have to subscribe to the list first. This is necessary to keep the

spam level down.

The address for mailing to list members is:

[email protected]

Bug reports and code contributions should be uploaded to the trackers at

http://sourceforge.net/projects/gnuplot/support

Please check previous bug reports if the bug you want to report has not been

already fixed in a newer version.

A mailing list for those interested in development version of gnuplot is:

[email protected]

When posting a question, please include full details of the gnuplot version,

the terminal type, and the operating system you are using. A short

self-contained script demonstrating the problem is often helpful.

2 New features

3 Features introduced in version 5.3

?new version_5.3

?new

Version 5.3 is the current development version. New features introduced here

will generally not appear in a supported release until version 5.4. Details

may change before that. However some features developed for 5.3 may be

back-ported for inclusion in incremental patch-level releases of the stable

version 5.2.x.

4 Support for 64-bit integer arithmetic

#start

#bAll evaluation of expressions and functions uses 64-integer arithmetic if

##supported by the platform.

#bInteger overflow is detected and handled according to user preference.

##See `overflow`.

#end

4 New plot styles and style options

#start

#bPlot style `with circles` can be used in 3D plots.

#bPlot style `with boxes` can be used in 3D plots.

#bCustomized contour line types. See `set cntrparam`.

#end

4 New commands and command options

?new commands

#start

#bNew options for showing the xy xz and yz planes in 3D plots.

##See `set walls`, `set grid vertical`.

#b`set table separator {tab|comma|"char"}` can be used to create csv files.

##See `plot with table`.

#b`set rgbmax <value>` controls interpretation of input RGB values.

#bnew formats descriptors tH tM tS handle relative times (interval lengths).

##See `time_specifiers`.

#bArray size can be implicit if initializer is present, e.g. `Array A = [1,2,3]`.

#bOptional radial clipping of line segments in polar mode. See `set clip`.

#bUser-specified translation of mouse coordinates (EXPERIMENTAL).

##See map_projection demo.

#end

4 New terminals and terminal options

#start

#b The `pcl5` terminal has been extended to support PCL5e/PCL5c printers and

## many modern gnuplot features.

#end

4 Other new features

#start

#bEnhanced text mode accepts \U+xxxx (xxxx is a 4 or 5 character hexadecimal)

##as representing a Unicode code point that is converted to the corresponding

##UTF-8 byte sequence on output. EXPERIMENTAL (implementation may change)

#end

3 Features introduced in version 5.2

?Features introduced in version 5.2

4 New plot styles and style options

?new plot styles

#start

#b 3D plot style `with zerrorfill`. See `zerrorfill`, `fenceplots` and

^ <a href="http://gnuplot.info/demo_5.2/zerror.html">

zerror demo.

^ </a>

#b Beeswarm plots. See `set jitter`, `beeswarm` and

^ <a href="http://gnuplot.info/demo_5.2/jitter.html">

beeswarm plot demo

^ </a>

#b The symbol used for individual points in a plot can be controlled by data values

## (see `pointtype variable`)

#end

4 New data pre-processing filters

?new filters

#start

#b Normalized frequency of occurrence in a data set (see `smooth fnormal`)

#b Automated binning of data (see `bins`)

#end

4 Polar mode improvements and extensions

?new polar mode features

#start

#b Polar coordinates may be used in label, arrow, and object definitions

#b `set [m]ttics` places ticmarks and labels on the perimeter of a polar plot. See

^ <a href="http://gnuplot.info/demo_5.2/ttics.html"> polar axis and ticlabels demo

^ </a>

#b `set rlabel` places a label above the r axis

#b Inverted `rrange` (i.e. set rrange [90:0]) allows use of celestial horizontal

## coordinates. See

^ <a href="http://gnuplot.info/demo_5.2/solar_path.html"> solar path demo

^ </a>

#b `set border polar` draws a solid line around the perimeter of a polar plot

#b `set theta` controls the position of theta = 0 around the perimeter of a

## polar plot and the sense (clockwise or anti-clockwise) of increasing theta

#end

4 Nonlinear coordinates systems

?new nonlinear coordinates

#start

#b Any plot axis can be assigned a pair of functions, possibly nonlinear, that

## describe the forward and reverse mapping to a linear range (see `set nonlinear`)

^ <a href="http://gnuplot.info/demo_5.2/nonlinear3.html">

Nonlinear x/y axis demo

^ </a>

#b The familiar command `set logscale` has been reimplemented as a special case

## nonlinear axis where the paired functions are log(x) and exp(x).

#end

4 New commands and command options

?new commands in 5.2

#start

#b Inside the bracketed clause of an iteration, `continue` jumps immediately

## to the next iteration, `break` immediately exits from the iteration

#b `toggle {<plotno> | "plottitle" | all}"` interactively enables or disables

## display of one element of the current plot (see `toggle`)

#b `save fit` replaces deprecated command `update`

#b `set table "outfile.name" append` will append subsequent tabulated plots to

## an existing text file rather replacing its contents

#b `set pm3d lighting` describes a lighting model with specular highlighting

## (see `lighting`)

#b `set minussign` tells gnuplot to use a special symbol in the current

## encoding to replace the ascii character '-' in negative numbers

#b `set micro` tells gnuplot to use a special symbol in the current encoding to

## replace the ascii character 'u' for the scientific notation prefix "micro"

## The special typographic symbols for micro and minussign are used only in axis

## tic labels and strings explicitly created with gprintf(). The byte sequence

## used to represent these characters depends on the current encoding.

#end

4 New data type "array"

?new features

#start

#b This gnuplot version introduces a new data type `array name[size]`.

## An array must be declared before use. Each array element A[i] may be a string,

## an integer, a real number, or a complex value. A single array may contain

## elements with different types. The cardinality operator |A| returns the size

## of array A. See `arrays`.

#end

4 New terminals and terminal options

#start

#b See `sixelgd` for description of a new terminal that supports interleaving

## plots with the command lines that generated them if gnuplot is run inside a

## vt340-compatible terminal emulator

#b The `domterm` terminal supports interleaving plots with the command lines

## that generated them if gnuplot is run inside an svg-aware terminal emulator

#b The `windows` terminal supports saving the current graph to a bitmap file

#b The `windows` terminal graph window can be docked to the wgnuplot text window

#b New (experimental) Direct2D/DirectWrite backend for the `windows` terminal

#b The `wxt` terminal supports exporting to an EMF file or printer on Windows

#b The `dumb` terminal supports ANSI colors for lines and fill area

#b The `tkcanvas` terminal has been rewritten to support many more modern gnuplot

## features, as well as new languages. (Since 5.0.3)

#end

4 Other new features

#start

#b An additional rotation angle `azimuth` affects the orientation of 3D plots.

## This can be set from the command line (see `set view azimuth`) or by dragging

## with the right mouse button.

#b gnuplot running under Windows can interpret Unicode (BMP) input scripts by

## converting them to the current encoding from `set encoding`, including UTF-8

#b Textboxes can be assigned a border color and fill color (see `set style textbox`)

#b Customized plot legends (see `plot title`, `set key`, `multiple keys`)

#b A sampling range specifier for plotting with pseudofile '+' can include a

## sampling interval. For example:

## plot sample [t=0:100:10] '+' using (t):(1):(label[t]) with labels

#b Pseudo-file '++' generates samples on the u and v axes, rather than x and y.

## This allows placement of multiple parametric surfaces in 3D that occupy

## distinct regions of Cartesian space. See `sampling.dem`.

#b ^R initiates a reverse-search through the history for the built-in readline

## which is used on Windows, too, see `command-line-editing`.

#b Revised printing support on Windows using `set output "PRN"`,

## see `windows printing`.

#end

3 Features introduced in version 5.0

?Features introduced in version 5.0

#start

#b The dot-dash pattern of a line can now be specified independent of other

## line properties. See `dashtype`, `set dashtype`, `set linetype`

#b The default sequence of colors used for successive elements in a plot is

## more easily distinguished by users with color-vision defects.

## The color sequence is under user control (see `set colorsequence`).

## This mechanism can also be used to generate monochrome plots

## (see `set monochrome`). In previous gnuplot versions `monochrome` could only

## be selected when changing the current terminal via `set terminal`.

#b New plot styles `with parallelaxes`, `with table`, and labeled contours.

#b New data pre-processing filter for monotonic cubic splines (see `smooth mcsplines`)

#b Text markup now supports bold and italic font settings in addition to

## subscript, superscript, font size and other previously available properties.

## Enhanced text mode is now enabled by default. See `enhanced text`.

## Text elements can be enclosed in a box (see `set style textbox`).

#b Interactive terminals support hypertext labels that only appear when the

## mouse hovers over the label's anchor point.

#b New coordinate system (Degrees, Minutes, Seconds). See `set xtics geographic`.

#b The default format for axis labels is "% h" ("$%h$" for LaTeX terminals).

## This format is like the C standard format %g except that the exponential term,

## if present, is written using a superscript. E.g. 1.2 x 10^5 rather than 1.2E05.

#b Command scripts may place in-line data in a named data block for repeated

## plotting. See `inline data`.

#b Support for 32-bit Alpha channel + RGB color #AARRGGBB. See `colorspec`.

#b Support for HSV color space via a translation function hsv2rgb(H,S,V).

#b Secondary axes (x2, y2) may be locked to the primary axis via a mapping

## function. In the simplest case this guarantees that the primary and secondary

## axis ranges are identical. In the general case it allows you to define a

## non-linear axis, something that previously was possible only for log scaling.

## See `set link`.

#b Each function in a plot command may optionally be preceded by a sampling

## range. This does not affect the overall range of the plot, only the range

## over which this function is sampled. See `plot` and `piecewise.dem`.

#b If the external library libcerf is available, it is used to provide complex

## math routines cerf, cdawson, erfi, faddeeva, and the Voigt profile

## VP(x,sigma,gamma).

#b The `import` command attaches a user-defined function name to a function

## provided by an external shared object (support is operating-system dependent).

## A template header and example source and make files for creating a suitable

## external shared object are provided in the demo collection.

#b Previous commands in the history list of an interactive session can be

## reexecuted by number. For example, `history !5` will reexecute the command

## numbered 5 in the `history` list.

#b Bit-shift operators >> and <<.

#b Shell invocation of gnuplot can pass parameters to a gnuplot script.

## gnuplot -c scriptfile.gp ARG1 ARG2 ARG3 ...

#end

2 Differences from version 4

?changes

?differences

Some changes introduced in version 5 may cause certain scripts written

for earlier versions of gnuplot to behave differently.

* Revised handling of input data containing NaN, inconsistent number of data

columns, or other unexpected content. See Note under `missing` for examples

and figures.

* Time coordinates are stored internally as the number of seconds relative to

the standard unix epoch 1-Jan-1970. Earlier versions of gnuplot used a

different epoch internally (1-Jan-2000). This change resolves inconsistencies

introduced whenever time in seconds was generated externally. The epoch

convention used by a particular gnuplot installation can be determined using

the command `print strftime("%F",0)`. Time is now stored to at least

millisecond precision.

* The function `timecolumn(N,"timeformat")` now has 2 parameters. Because the

new second parameter is not associated with any particular data axis, this

allows using the `timecolumn` function to read time data for reasons other than

specifying the x or y coordinate. This functionality replaces the command

sequence `set xdata time; set timefmt "timeformat"`. It allows combining time

data read from multiple files with different formats within a single plot.

* The `reverse` keyword of the `set [axis]range` command affects only

autoscaling. It does not invert or otherwise alter the meaning of a command

such as `set xrange [0:1]`. If you want to reverse the direction of the

x axis in such a case, say instead `set xrange [1:0]`.

* The `call` command is provides a set of variables ARGC, ARG0, ..., ARG9.

ARG0 holds the name of the script file being executed. ARG1 to ARG9 are string

variables and thus may either be referenced directly or expanded as macros,

e.g. @ARG1. The contents of ARG0 ... ARG9 may alternatively be accessed as

array elements ARGV[0] ... ARGV[ARGC]. An older gnuplot convention of

referencing call parameters as tokens $0 ... $9 is deprecated.

* The optional bandwidth for the kernel density smoothing option is taken from

a keyword rather than a data column. See `smooth kdensity`.

2 Deprecated syntax

?deprecated syntax

?backwards compatibility

?compatibility

Gnuplot version 4 deprecated certain syntax used in earlier versions but

provided a configuration option that allowed backward compatibility.

Support for the old syntax has now been removed.

Deprecated in version 4 and removed in version 5:

set title "Old" 0,-1

set data linespoints

plot 1 2 4 # horizontal line at y=1

Current equivalent:

TITLE = "New"

set title TITLE offset char 0, char -1

set style data linespoints

plot 1 linetype 2 pointtype 4

Deprecated, present in version 5.0 if configured --enable-backwards-compatibility

if (defined(VARNAME)) ...

set style increment user

plot 'file' thru f(x)

call 'script' 1.23 ABC

(in script: print $0, "$1", "number of args = $#")

Current equivalent:

if (exists("VARNAME")) ...

set linetype

plot 'file' using 1:(f(column(2)))

call 'script' 1.23 "ABC"

(in script: print ARG1, ARG2, "number of args = ", ARGC

2 Demos and Online Examples

?demos

?online examples

?examples

The `gnuplot` distribution contains a collection of examples in the `demo`

directory. You can browse on-line versions of these examples produced by the

png, svg, and canvas terminals at

^ <a href="http://gnuplot.info/demos/">

http://gnuplot.info/demos

^ </a>

The commands that produced each demo plot are shown next to the plot, and

the corresponding gnuplot script can be downloaded to serve as a model for

generating similar plots.

2 Batch/Interactive Operation

?batch/interactive

?command line options

`Gnuplot` may be executed in either batch or interactive modes, and the two

may even be mixed together on many systems.

Any command-line arguments are assumed to be either program options (first

character is -) or names of files containing `gnuplot` commands. The option

-e "command" may be used to force execution of a gnuplot command. Each file

or command string will be executed in the order specified. The special

filename "-" is indicates that commands are to be read from stdin.

`Gnuplot` exits after the last file is processed. If no load files and no

command strings are specified, `gnuplot` accepts interactive input from

stdin.

Both the `exit` and `quit` commands terminate the current command file and

`load` the next one, until all have been processed.

Examples:

To launch an interactive session:

gnuplot

To launch a batch session using two command files "input1" and "input2":

gnuplot input1 input2

To launch an interactive session after an initialization file "header" and

followed by another command file "trailer":

gnuplot header - trailer

To give `gnuplot` commands directly in the command line, using the "-persist"

option so that the plot remains on the screen afterwards:

gnuplot -persist -e "set title 'Sine curve'; plot sin(x)"

To set user-defined variables a and s prior to executing commands from a file:

gnuplot -e "a=2; s='file.png'" input.gpl

2 Canvas size

?canvas size

?canvas

?set term size

In earlier versions of gnuplot, some terminal types used the values from

`set size` to control also the size of the output canvas; others did not.

The use of 'set size' for this purpose was deprecated in version 4.2.

Almost all terminals now behave as follows:

`set term <terminal_type> size <XX>, <YY>` controls the size of the output

file, or "canvas". By default, the plot will fill this canvas.

`set size <XX>, <YY>` scales the plot itself relative to the size of the

canvas. Scale values less than 1 will cause the plot to not fill the entire

canvas. Scale values larger than 1 will cause only a portion of the plot to

fit on the canvas. Please be aware that setting scale values larger than 1

may cause problems.

The major exception to this convention is the PostScript driver, which

by default continues to act as it did in earlier versions. Be warned that

some future version of gnuplot may change the default behaviour of the

PostScript driver as well.

Example:

set size 0.5, 0.5

set term png size 600, 400

set output "figure.png"

plot "data" with lines

These commands produce an output file "figure.png" that is 600 pixels

wide and 400 pixels tall. The plot will fill the lower left quarter of this

canvas. This is consistent with the way multiplot mode has always worked.

2 Command-line-editing

?line-editing

?editing

?command-line-editing

Command-line editing and command history are supported using either an

external gnu readline library, an external BSD libedit library, or a

built-in equivalent. This choice is a configuration option at the time

gnuplot is built.

The editing commands of the built-in version are given below. Please note that

the action of the DEL key is system-dependent. The gnu readline and BSD libedit

libraries have their own documentation.

@start table - first is interactive cleartext form

`Line-editing`:

^B moves back a single character.

^F moves forward a single character.

^A moves to the beginning of the line.

^E moves to the end of the line.

^H deletes the previous character.

DEL deletes the current character.

^D deletes current character, sends EOF if the line is empty.

^K deletes from current position to the end of line.

^L redraws line in case it gets trashed.

^U deletes the entire line.

^W deletes previous word.

^V inhibits the interpretation of the following key as editing command.

TAB performs filename-completion.

`History`:

^P moves back through history.

^N moves forward through history.

^R starts a backward-search.

#\begin{tabular}{|cl|} \hline

#\multicolumn{2}{|c|}{Command-line Editing Commands} \\ \hline \hline

#Character & Function \\ \hline

# & \multicolumn{1}{|c|}{Line Editing}\\ \cline{2-2}

#\verb~^B~ & move back a single character.\\

#\verb~^F~ & move forward a single character.\\

#\verb~^A~ & move to the beginning of the line.\\

#\verb~^E~ & move to the end of the line.\\

#\verb~^H~ & delete the previous character.\\

#\verb~DEL~ & delete the current character.\\

#\verb~^D~ & delete current character. EOF if line is empty.\\

#\verb~^K~ & delete from current position to the end of line.\\

#\verb~^L~ & redraw line in case it gets trashed.\\

#\verb~^U~ & delete the entire line. \\

#\verb~^W~ & delete previous word. \\

#\verb~^V~ & inhibits the interpretation of the following key as editing command. \\

#\verb~TAB~ & performs filename-completion. \\ \hline

# & \multicolumn{1}{|c|}{History} \\ \cline{2-2}

#\verb~^P~ & move back through history.\\

#\verb~^N~ & move forward through history.\\

#\verb~^R~ & starts a backward-search.\\

%c l .

%Character@Function

%_

%@Line Editing

%^B@move back a single character.

%^F@move forward a single character.

%^A@move to the beginning of the line.

%^E@move to the end of the line.

%^H@delete the previous character.

%DEL@delete the current character.

%^D@delete current character. EOF if line is empty.

%^K@delete from current position to the end of line.

%^L@redraw line in case it gets trashed.

%^U@delete the entire line.

%^W@delete previous word.

%_

%^V@inhibits the interpretation of the following key as editing command.

%TAB@performs filename-completion.

%_

%@History

%^P@move back through history.

%^N@move forward through history.

%^R@starts a backward-search.

@end table

^<table align="center" border="1" rules="groups" frame="hsides" cellpadding="3">

^<colgroup>

^ <col align="center">

^ <col align="left">

^</colgroup>

^<thead>

^<tr> <th>Character</th> <th>Function</th></tr>

^</thead>

^<tbody>

^<tr> <td></td> <th>Line Editing</th></tr>

^<tr> <td><tt>^B</tt></td> <td>move back a single character.</td></tr>

^<tr> <td><tt>^F</tt></td> <td>move forward a single character.</td></tr>

^<tr> <td><tt>^A</tt></td> <td>move to the beginning of the line.</td></tr>

^<tr> <td><tt>^E</tt></td> <td>move to the end of the line.</td></tr>

^<tr> <td><tt>^H</tt></td> <td>delete the previous character.</td></tr>

^<tr> <td><tt>DEL</tt></td> <td>delete the current character.</td></tr>

^<tr> <td><tt>^D</tt></td> <td>delete current character. EOF if line is empty</td></tr>

^<tr> <td><tt>^K</tt></td> <td>delete from current position to the end of line.</td></tr>

^<tr> <td><tt>^L</tt></td> <td>redraw line in case it gets trashed.</td></tr>

^<tr> <td><tt>^U</tt></td> <td>delete the entire line.</td></tr>

^<tr> <td><tt>^W</tt></td> <td>delete previous word.</td></tr>

^<tr> <td><tt>^V</tt></td> <td>inhibits the interpretation of the following key as editing command.</td></tr>

^<tr> <td><tt>TAB</tt></td> <td>performs filename-completion.</td></tr>

^</tbody>

^<tbody>

^<tr> <th></th> <th>History</th></tr>

^<tr> <td><tt>^P</tt></td> <td>move back through history.</td></tr>

^<tr> <td><tt>^N</tt></td> <td>move forward through history.</td></tr>

^<tr> <td><tt>^R</tt></td> <td>starts a backward-search.</td></tr>

^</tbody>

^</table>

2 Comments

?comments

The comment character `#` may appear almost anywhere in a command line, and

`gnuplot` will ignore the rest of that line. A `#` does not have this effect

inside a quoted string. Note that if a commented line ends in '\' then the

subsequent line is also treated as part of the comment.

See also `set datafile commentschars` for specifying a comment character for

data files.

2 Coordinates

?coordinates

=axes

The commands `set arrow`, `set key`, `set label` and `set object` allow you

to draw something at an arbitrary position on the graph. This position is

specified by the syntax:

{<system>} <x>, {<system>} <y> {,{<system>} <z>}

Each <system> can either be `first`, `second`, `polar`, `graph`, `screen`, or

`character`.

`first` places the x, y, or z coordinate in the system defined by the left

and bottom axes; `second` places it in the system defined by the x2,y2 axes

(top and right); `graph` specifies the area within the axes---0,0 is bottom

left and 1,1 is top right (for splot, 0,0,0 is bottom left of plotting area;

use negative z to get to the base---see `set xyplane`); `screen`

specifies the screen area (the entire area---not just the portion selected by

`set size`), with 0,0 at bottom left and 1,1 at top right. `character`

coordinates are used primarily for offsets, not absoute positions.

The `character` vertical and horizontal size depend on the current font.

`polar` causes the first two values to be interpreted as angle theta and radius

r rather than as x and y. This could be used, for example, to place labels on

a 2D plot in polar coordinates or a 3D plot in cylindrical coordinates.

If the coordinate system for x is not specified, `first` is used. If the

system for y is not specified, the one used for x is adopted.

In some cases, the given coordinate is not an absolute position but a

relative value (e.g., the second position in `set arrow` ... `rto`). In

most cases, the given value serves as difference to the first position.

If the given coordinate belongs to a log-scaled axis, a relative value is

interpreted as multiplier. For example,

set logscale x

set arrow 100,5 rto 10,2

plots an arrow from position 100,5 to position 1000,7 since the x axis is

logarithmic while the y axis is linear.

If one (or more) axis is timeseries, the appropriate coordinate should

be given as a quoted time string according to the `timefmt` format string.

See `set xdata` and `set timefmt`. `Gnuplot` will also accept an integer

expression, which will be interpreted as seconds relative to 1 January 1970.

2 Datastrings

?datastrings

Data files may contain string data consisting of either an arbitrary string

of printable characters containing no whitespace or an arbitrary string of

characters, possibly including whitespace, delimited by double quotes.

The following line from a datafile is interpreted to contain four

columns, with a text field in column 3:

1.000 2.000 "Third column is all of this text" 4.00

Text fields can be positioned within a 2-D or 3-D plot using the commands:

plot 'datafile' using 1:2:4 with labels

splot 'datafile' using 1:2:3:4 with labels

A column of text data can also be used to label the ticmarks along one or more

of the plot axes. The example below plots a line through a series of points

with (X,Y) coordinates taken from columns 3 and 4 of the input datafile.

However, rather than generating regularly spaced tics along the x axis

labeled numerically, gnuplot will position a tic mark along the x axis at the

X coordinate of each point and label the tic mark with text taken from column

1 of the input datafile.

set xtics

plot 'datafile' using 3:4:xticlabels(1) with linespoints

=columnheader

There is also an option that will interpret the first entry in a column of

input data (i.e. the column heading) as a text field, and use it as the key

title for data plotted from that column. The example given below will use the

first entry in column 2 to generate a title in the key box, while processing

the remainder of columns 2 and 4 to draw the required line:

plot 'datafile' using 1:(f($2)/$4) with lines title columnhead(2)

Another example:

plot for [i=2:6] 'datafile' using i title "Results for ".columnhead(i)

This use of column headings is automated by `set key autotitle columnhead`.

See `labels`, `using xticlabels`, `plot title`, `using`, `key autotitle`.

2 Enhanced text mode

?enhanced text

?enhanced

?text_markup

?markup

?bold

?italic

Many terminal types support an enhanced text mode in which additional

formatting information is embedded in the text string. For example, "x^2"

will write x-squared as we are used to seeing it, with a superscript 2.

This mode is selected by default when you set the terminal, but may be

toggled afterward using "set termoption [no]enhanced", or by marking

individual strings as in "set label 'x_2' noenhanced".

@start table - first is interactive cleartext form

Control Examples Explanation

^ a^x superscript

_ a_x subscript

@ @x or a@^b_{cd} phantom box (occupies no width)

& &{space} inserts space of specified length

~ ~a{.8-} overprints '-' on 'a', raised by .8

times the current fontsize

{/Times abc} print abc in font Times at current size

{/Times*2 abc} print abc in font Times at twice current size

{/Times:Italic abc} print abc in font Times with style italic

{/Arial:Bold=20 abc} print abc in boldface Arial font size 20

\U+ \U+221E Unicode point U+221E (INFINITY)

#\begin{tabular}{|clll|} \hline

#\multicolumn{4}{|c|}{Enhanced Text Control Codes} \\ \hline

#Control & Example & Result & Explanation \\ \hline

#\verb~^~ & \verb~a^x~ & $a^x$ & superscript\\

#\verb~_~ & \verb~a_x~ & $a_x$ & subscript\\

#\verb~@~ & \verb~a@^b_{cd}~ & $a^b_{cd}$ &phantom box (occupies no width)\\

#\verb~&~ & \verb~d&{space}b~ & d\verb*+ +b & inserts space of specified length\\

#\verb|~| & \verb|~a{.8-}| & $\tilde{a}$ & overprints '-' on 'a', raised by .8\\

#\verb~ ~ & \verb~ ~ & ~ ~ & times the current fontsize\\

#\verb| | & \verb|{/Times abc}| & {\rm abc} & print abc in font Times at current size\\

#\verb| | & \verb|{/Times*2 abc}| & \Large{\rm abc} & print abc in font Times at twice current size\\

#\verb| | & \verb|{/Times:Italic abc}| & {\it abc} & print abc in font Times with style italic\\

#\verb| | & \verb|{/Arial:Bold=20 abc}| & \Large\textsf{\textbf{abc}} & print abc in boldface Arial font size 20\\

#\verb|\U+| & \verb|\U+221E| & $\infty$ & Unicode point U+221E INFINITY\\

%c c l .

C ugly - doc2ms uses @ for column separator, but here we

C need @ in table, so end and restart the table !

%.TE

%.TS

%center box tab ($) ;

%c c l .

%Control$Examples$Explanation

%_

%^$a^x$superscript

%\&_$a\&_x$subscript

% @ $ @x or a\&@^b\&_{cd}$phantom box (occupies no width)

% & $ &{space}$inserts space of specified length

% ~ $ ~a{.8-}$overprints '-' on 'a', raised by .8

% $ $times the current fontsize

@end table

^<table align="center" border="1" rules="groups" frame="hsides" cellpadding="3">

^<colgroup>

^ <col align="center">

^ <col align="center">

^ <col align="left">

^</colgroup>

^<thead>

^<tr> <th>Control</th> <th>Examples</th> <th>Explanation</th></tr>

^</thead>

^<tbody>

^<tr> <td><tt> ^ </tt></td> <td><tt>a^x</tt></td> <td>superscript</td></tr>

^<tr> <td><tt> _ </tt></td> <td><tt>a_x</tt></td> <td>subscript</td></tr>

^<tr> <td><tt> @ </tt></td> <td><tt> @x</tt> or <tt>a@^b_{cd}</tt></td> <td>phantom box (occupies no width)</td></tr>

^<tr> <td><tt> &amp;</tt></td> <td><tt> &amp;{space}</tt></td> <td>inserts space of specified length</td></tr>

^<tr> <td><tt> ~ </tt></td> <td><tt> ~a{.8-}</tt></td> <td>overprints '-' on 'a', raised by .8<br>times the current fontsize</td></tr>

^</tbody>

^</table>

The markup control characers act on the following single character or

bracketed clause. The bracketed clause may contain a string of characters with

no additional markup, e.g. 2^{10}, or it may contain additional markup that

changes font properties. This example illustrates nesting one bracketed clause

inside another to produce a boldface A with an italic subscript i, all in the

current font. If the clause introduced by :Normal were omitted the subscript

would be both italic and boldface.

{/:Bold A_{/:Normal{/:Italic i}}}

Font specifiers MUST be preceeded by a '/' character that immediately follows

the opening '{'.

The phantom box is useful for a@^b_c to align superscripts and subscripts

but does not work well for overwriting an accent on a letter. For the latter,

it is much better to use an encoding (e.g. iso_8859_1 or utf8) that contains

a large variety of letters with accents or other diacritical marks. See

`set encoding`. Since the box is non-spacing, it is sensible to put the shorter

of the subscript or superscript in the box (that is, after the @).

Space equal in length to a string can be inserted using the '&' character.

Thus

'abc&{def}ghi'

would produce

'abc ghi'.

The '~' character causes the next character or bracketed text to be

overprinted by the following character or bracketed text. The second text

will be horizontally centered on the first. Thus '~a/' will result in an 'a'

with a slash through it. You can also shift the second text vertically by

preceding the second text with a number, which will define the fraction of the

current fontsize by which the text will be raised or lowered. In this case

the number and text must be enclosed in brackets because more than one

character is necessary. If the overprinted text begins with a number, put a

space between the vertical offset and the text ('~{abc}{.5 000}'); otherwise

no space is needed ('~{abc}{.5---}'). You can change the font for one or

both strings ('~a{.5 /*.2 o}'---an 'a' with a one-fifth-size 'o' on top---and

the space between the number and the slash is necessary), but you can't

change it after the beginning of the string. Neither can you use any other

special syntax within either string. You can, of course, use control

characters by escaping them (see below), such as '~a{\^}'

You can escape control characters using \, e.g., \\, \{, and so on.

See `escape sequences` below.

Note that strings in double-quotes are parsed differently than those enclosed

in single-quotes. The major difference is that backslashes may need to be

doubled when in double-quoted strings.

The file "ps_guide.ps" in the /docs/psdoc subdirectory of the gnuplot source

distribution contains more examples of the enhanced syntax, as does the demo

^ <a href="http://www.gnuplot.info/demo/enhanced_utf8.html">

`enhanced_utf8.dem`

^ </a>

3 Escape sequences

?escape sequences

?enhanced text escape sequences

?unicode

The backslash character \ is used to escape single byte character codes or

Unicode entry points.

The form \ooo (where ooo is a 3 character octal value) can be used to index a

known character code in a specific font encoding. For example the Adobe Symbol

font uses a custom encoding in which octal 245 represents the infinity symbol.

You could embed this in an enhanced text string by giving the font name and the

character code "{/Symbol \245}". This is mostly useful for the PostScript

terminal, which cannot easily handle UTF-8 encoding.

You can specify a character by its Unicode code point as \U+hhhh, where hhhh

is the 4 or 5 character hexadecimal code point. For example the code point for

the infinity symbol is \U+221E. This will be converted to a UTF-8 byte

sequence on output if appropriate. In a UTF-8 environment this mechanism

is not needed for printable special characters since they are handled in a

text string like any other character. However it is useful for combining forms

or supplemental diacritical marks (e.g. an arrow over a letter to represent

a vector). See `set encoding`, `utf8`, and the

^ <a href="http://www.gnuplot.info/demo_5.3/unicode.html">

online unicode demo.

^ </a>

2 Environment

?environment

A number of shell environment variables are understood by `gnuplot`. None of

these are required, but may be useful.

GNUTERM, if defined, is used to set the terminal type on start-up.

Starting with version 5.2 the entire string in GNUTERM is passed to

"set term" so that terminal options may be included. E.g.

GNUTERM="postscript eps color size 5in, 3in"

This can be overridden by the ~/.gnuplot (or equivalent) start-up file

(see `startup`) and of course by later explicit `set term` commands.

GNUHELP may be defined to be the pathname of the HELP file (gnuplot.gih).

On VMS, the logical name GNUPLOT$HELP should be defined as the name of the

help library for `gnuplot`. The `gnuplot` help can be put inside any VMS

system help library.

On Unix, HOME is used as the name of a directory to search for a .gnuplot

file if none is found in the current directory. On MS-DOS, Windows and OS/2,

GNUPLOT is used. On Windows, the NT-specific variable USERPROFILE is also

tried. VMS, SYS$LOGIN: is used. Type `help startup`.

On Unix, PAGER is used as an output filter for help messages.

On Unix, SHELL is used for the `shell` command. On MS-DOS and OS/2, COMSPEC

is used for the `shell` command.

`FIT_SCRIPT` may be used to specify a `gnuplot` command to be executed when a

fit is interrupted---see `fit`. `FIT_LOG` specifies the default filename of the

logfile maintained by fit.

GNUPLOT_LIB may be used to define additional search directories for data

and command files. The variable may contain a single directory name, or

a list of directories separated by a platform-specific path separator,

eg. ':' on Unix, or ';' on DOS/Windows/OS/2 platforms. The contents

of GNUPLOT_LIB are appended to the `loadpath` variable, but not saved

with the `save` and `save set` commands.

Several gnuplot terminal drivers access TrueType fonts via the gd library.

For these drivers the font search path is controlled by the environmental

variable GDFONTPATH. Furthermore, a default font for these drivers may be

set via the environmental variable GNUPLOT_DEFAULT_GDFONT.

The postscript terminal uses its own font search path. It is controlled by

the environmental variable GNUPLOT_FONTPATH. The format is the same as for

GNUPLOT_LIB. The contents of GNUPLOT_FONTPATH are appended to the `fontpath`

variable, but not saved with the `save` and `save set` commands.

GNUPLOT_PS_DIR is used by the postscript driver to search for external

prologue files. Depending on the build process, gnuplot contains either a

built-in copy of those files or a default hardcoded path. You can use this

variable have the postscript terminal use custom prologue files rather than

the default files. See `postscript prologue`.

2 Expressions

?expressions

?division

In general, any mathematical expression accepted by C, FORTRAN, Pascal, or

BASIC is valid. The precedence of these operators is determined by the

specifications of the C programming language. White space (spaces and tabs)

is ignored inside expressions.

Note that gnuplot uses both "real" and "integer" arithmetic, like FORTRAN and

C. Integers are entered as "1", "-10", etc; reals as "1.0", "-10.0", "1e1",

3.5e-1, etc. The most important difference between the two forms is in

division: division of integers truncates: 5/2 = 2; division of reals does

not: 5.0/2.0 = 2.5. In mixed expressions, integers are "promoted" to reals

before evaluation: 5/2e0 = 2.5. The result of division of a negative integer

by a positive one may vary among compilers. Try a test like "print -5/2" to

determine if your system always rounds down (-5/2 yields -3) or always rounds