Gforth uses these environment variables:
GFORTHHIST – (Unix systems only) specifies the path for the
history file .gforth-history. Default:
$HOME/.local/share/gforth/history.
GFORTHPATH – specifies the path used when searching for the
gforth image file and for Forth source-code files (usually ‘.’, the
current working directory). Path separator is ‘:’, a typical path
would be /usr/local/share/gforth/1.0:..
LANG – see LC_CTYPE
LC_ALL – see LC_CTYPE
LC_CTYPE – If this variable contains “UTF-8” on Gforth
startup, Gforth uses the UTF-8 encoding for strings internally and
expects its input and produces its output in UTF-8 encoding, otherwise
the encoding is 8bit (see see Xchars and Unicode). If this
environment variable is unset, Gforth looks in LC_ALL, and if
that is unset, in LANG.
GFORTHSYSTEMPREFIX – specifies what to prepend to the argument
of system before passing it to C’s system(). Default:
"./$COMSPEC /c " on Windows, "" on other OSs. The
prefix and the command are directly concatenated, so if a space
between them is necessary, append it to the prefix.
GFORTH – used by gforthmi, See gforthmi.
GFORTHD – used by gforthmi, See gforthmi.
TMP, TEMP - (non-Unix systems only) used as a potential
location for the history file.
All the Gforth environment variables default to sensible values if they are not set.