concatenation - How to merge/combine files with extensions .001, .002, .003.. etc?

Possible Duplicate:
Good free software that will join .001 files?

There are files on sites like rapidshare which have extensions like .001, .002, .003? They seem to be split by some tool. How to merge these files?

Answer

The files have likely been split by a compression program. 7-Zip should handle them fine. They could also have been split with hjsplit or a similar tool, but 7-zip should handle the files.