The environment variable GCAL can hold a set of default options for Gcal (see Environment Variable GCAL). These options are interpreted first at program start-up, and some can be overwritten by explicit command line arguments or values found in a @file response file. See Command line arguments, and Response file, for further information.
GCAL="-i @color -b 3"; export GCAL
setenv GCAL "-i @color -b 3"
set GCAL=-i @color -b 3
On Vax/VMS, the name of the environment variable is GCAL_OPT, to avoid a conflict with the symbol GCAL set for invocation of the program.
define GCAL_OPT "-i @color -b 3"