close

Closes the current file and skips to the next in the stream. Trying to
close a file that has already been closed causes an +IOError+ to be
raised.

$ ruby argf.rb foo bar

ARGF.filename  #=> "foo"
ARGF.close
ARGF.filename  #=> "bar"
ARGF.close
ARGF.close     #=> closed stream (IOError)