.BG
.FN interactive
.TL
Test For Interactive Execution of S
.CS
interactive()
.RT
logical; `TRUE' if the input to S is an interactive
terminal, `FALSE' if it is not.
.PP
Use `interactive' to prevent inappropriate
execution.
For example, the `menu' and `browser' functions
only work when executed interactively.
.EX
if(!interactive()) stop("must be interactive")
.WR
