Na página de manual (para o tcsh):
> name
>! name
>& name
>&! name
The file name is used as standard output. If the file does not
exist then it is created; if the file exists, it is truncated,
its previous contents being lost.
If the shell variable noclobber is set, then the file must not
exist or be a character special file (e.g., a terminal or
'/dev/null') or an error results. This helps prevent acciden‐
tal destruction of files. In this case the '!' forms can be
used to suppress this check.
The forms involving '&' route the diagnostic output into the
specified file as well as the standard output. name is
expanded in the same way as '<' input filenames are
Portanto, ele redireciona stdout e stderr para o arquivo fornecido, sobrescrevendo a noclobber check.