mktemp [template]

  provides the mktemp function for systems which do not provide such a
  UNIX command tool.  mktemp constructs the name of a unique file and
  returns it on stdout.  By default, the filename will be
  /tmp/tmp.XXXXXX where XXXXXX is substituted with a string of
  characters to enforce uniqueness.  If the template filename is
  provided, consisting of a valid filename ending in .XXXXXX, then
  this template is used to construct the temporary file.