usage: cleverrename [-fi] [-l label] [-m mode] [-n] [-t filter_tcl_script]
                    [-T filter_tcl_script] [-uv]
   -f:         Force writing of output even if the output file is not
               writable. This controls only the permissions on the output
               file, not its directory. This option may still fail if the
               output directory is not writable.
   -i:         Disable input barriers.  See on-line documentation for more
               information on input barriers.
   -l:         The label is ignored. It is used to annotate the command line.
   -m:         UNIX: set access mode for output files. The argument 'mode'
               should be in octal and has the same form as for chmod().
               WindowsNT: the access mode for output files is set to `Read
               Only'. The argument is ignored. By default, the mode is set to
               allow writing.
   -n:         Do not activate VIL
   -t:         Use script as filter.  Output is the filtered input. See man
               page for information on filter scripts. 
   -T:         Same as -t, but copies unfiltered input
   -u:         Unlink old file if there is a change.  Useful when the output
               is an executable which may be in use.
   -v:         Verbose flag.