interactive
Test For Interactive Execution
Description
Returns a logical value stating whether the engine is being used interactively
or in batch mode.
Usage
interactive()
Details
Use interactive to prevent inappropriate
execution.
For example, the menu and browser functions
work only when executed interactively.
interactive returns
TRUE if the engine is started
interactively, without using the
-e or
-f options,
and if the standard input is a terminal (as determined by the
isatty function).
(interactive returns TRUE if the engine is started with the --interactive option,
Even if these are not true.)
Value
a logical value: TRUE if the engine is being used interactively,
FALSE if it is not.
See Also
Examples
if(!interactive()) stop("must be interactive")