a character String giving the file path. If it Is Of the
form "|cmd", the output Is piped To the command given by cmd. If it Is NULL,
Then no external file Is created (effectively, no drawing occurs), but the
device may still be queried (e.g., For size Of text).
For use with onefile = FALSE give a C integer format such as "Rplot%03d.pdf"
(the default in that case). (See postscript for further details.)
Tilde expansion(see path.expand) Is done. An input with a marked encoding Is
converted to the native encoding Or an error Is given.