gnuplot is a command-driven interactive function and data plotting program.
It is case sensitive (commands and function names written in lowercase are
not the same as those written in CAPS). All command names may be abbreviated
as long as the abbreviation is not ambiguous. Any number of commands may
appear on a line (with the exception that load or call must be the final
command), separated by semicolons (;). Strings are indicated with quotes.
They may be either single or double quotation marks, e.g.,
load "filename"
cd 'dir'
although there are some subtle differences (see syntax for more details).
Any command-line arguments are assumed to be names of files containing
gnuplot commands, with the exception of standard X11 arguments, which are
processed first. Each file is loaded with the load command, in the order
specified. gnuplot exits after the last file is processed. When no load
files are named, gnuplot enters into an interactive mode. The special
filename "-" is used to denote standard input. See "help batch/interactive"
for more details.
Many gnuplot commands have multiple options. These options must appear in
the proper order, although unwanted ones may be omitted in most cases. Thus
if the entire command is "command a b c", then "command a c" will probably
work, but "command c a" will fail.
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
comment). 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 on-line help on any topic, type help followed by the name of the topic
or just help or ? to get a menu of available topics.
The new gnuplot user should begin by reading about plotting (if on-line,
type help plotting).