Unsets a global variable from the current shell. These variables can
be accessed from any program executing at any time.
These variables are usually not saved in the ENVARC: directory, hence they
can only be used by programs during the current execution of the
operating system. If set using SAVE argument, the variable is also saved
in ENVARC: and can then be deleted there by UnSetEnv with the SAVE argument.
If no parameter is specified, the current list of global variables
UnSetEnv EDITOR SAVE
Any program that accesses the variable "EDITOR" (like More and
MultiView) are able to find out the name of the text-editor the
user would like to use, by examining the contents of the variable.
This command would delete this variable in Ram (in ENV:) _and_ in
ENVARC: (assuming it was already set there, for example by the use
of the SAVE argument of SetEnv).