If a file equation is not used to specify the characteristics
of an output redirection, file the following are taken as defaults:
256-byte, variable length, ASCII records
When output is redirected using the > filename redirection
specification to a temporary file which already exists,
the following defaults apply to the open:
If the >>filename specification is used instead, APPEND access is
requested instead of WRITE.
A default also exists for input redirection. A file to which input
has been redirected is opened by first attempting to open a
temporary file with the name specified. This makes default input
redirection consistent with default output redirection. If no such
temporary file exists, an attempt is made to open a permanent file
with that name.
When input is redirected, the file must exist and is opened with
the following defaults:
Look for a temporary file first, then an old permanent file
