When gnuplot is run, it looks for an initialization file to load. This
file is called .gnuplot on Unix and AmigaOS systems, and GNUPLOT.INI on
other systems. If this file is not found in the current directory, the
program will look for it in the home directory (under AmigaOS,
Atari(single)TOS, MS-DOS and OS/2, the environment variable gnuplot should
contain the name of this directory). Note: if NOCWDRC is defined during the
installation, gnuplot will not read from the current directory.
If the initialization file is found, gnuplot executes the commands in it.
These may be any legal gnuplot commands, but typically they are limited to
setting the terminal and defining frequently-used functions or variables.