Utility allowing to peak a part of a file and copy or append it to another
file. The format is :

 CUT From-file To-file length offset [/A]

 To-file will have added up to length bytes of From-file, starting at offset.
If the switch /A is specified, then datas will be appended to To-file,
otherwise To-file will be replaced.

 This small utility is useful to take parts or file, or to do copy/paste
with either binary nor ascii files.

 Together with the specification of the offset in the XGET command, in case
of crash, first note the amount of datas already received (ie : 50300), save
the part of the file already received, and then ask "XGET filename 50000".
The transfer will start at offset 50000 and then you will be able to receive
the end of the file. The paste the two parts, either with COPY command or
with the CUT command. It is more secure to cut the first received part before
as the last bytes should be garbaged.