Controlling redirection
The command:
set noclobber
indicates that you do not
want the > redirection operator to overwrite existing files.
When this option is on and you specify the construct >file,
the redirection works only if file does not exist. If you
have this option on and you really do want to redirect output into
an existing file, you must use >|file (with an "or"
bar after the >) to indicate output redirection.