mkstemp creates a temporary file using mkstemp(3), or if the -suffix switch is available and used,
mkstemps(3). The file name identifies a unique, newly created file, and always contains 6 characters
that appear to be random.
The -directory switch specifies a directory in which to create the file.
The -prefix switch specifies an initial part, before the 6 characters, of the file name.
The -suffix switch is only supported on platforms that provide the mkstemps(3) library function. It
specifies a suffix to appear after the 6 characters; if it should begin with a special character such as
a period, that must be explicit in suffix.
Unlike arguments to most switches of other nmh commands, the arguments to mkstemp switches can begin with
a dash.