2.2 Customizing Scheme
You can customize your setup by using a variety of tools:
Many parameters, like memory usage and the location of libraries, may be
varied by command-line options. See Command-Line Options.
Shell scripts. You might like to write scripts
that invoke Scheme with your favorite command-line options. For
example, you might not have enough memory to run Edwin or the compiler
with its default memory parameters (it will print something like “Not
enough memory for this configuration” and halt when started), so you
can write a shell script that will
invoke Scheme with the appropriate --heap and other parameters.
Scheme supports init files: an init file is a file containing
Scheme code that is loaded when Scheme is started, immediately after the
identification banner, and before the input prompt is printed. This
file is stored in your home directory, which is normally specified by
HOME environment variable. Under unix, the file is called
In addition, when Edwin starts up, it loads a separate init file from
your home directory into the Edwin environment. This file is called
.edwin under unix (see Starting Edwin).
You can use both of these files to define new procedures or commands, or
to change defaults in the system.
The --no-init-file command-line option causes Scheme to ignore
the .scheme.init file (see Command-Line Options).
- Environment variables. Most microcode parameters, and some
runtime system and Edwin parameters, can be specified by means of
environment variables. See Environment Variables.
With some window managers under X11, it is possible to create icons
that invoke Scheme with different parameters.