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## Environment

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

GNUTERM, if defined, is passed to "set term" on start-up. This can be overridden by a system or personal initialization file (see startup) and of course by later explicit set term commands. Terminal options may be included. E.g.

         bash$ export GNUTERM="postscript eps color size 5in, 3in"

GNUHELP, if defined, sets the pathname of the HELP file (gnuplot.gih).

Initialization at start-up may search for configuration files $HOME/.gnuplot, and $XDG_CONFIG_HOME/gnuplot/gnuplotrc. On MS-DOS, Windows and OS/2, files in GNUPLOT or USERPROFILE are searched. For more details see 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.

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 (see fonts). For these terminals GDFONTPATH and GNUPLOT_DEFAULT_GDFONT may affect font selection.

The postscript terminal uses its own font search path. It is controlled by the environmental variable GNUPLOT_FONTPATH.

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 to have the postscript terminal use custom prologue files rather than the default prologue files. See postscript prologue.