CRUSH is an archiving utility for DOS. It was developed by Jeff Rollason and PocketWare, and distributed as shareware.
Not to be confused with:
- The "crushed" compression method used by PAK (ARC extension)
- ARQ Crusher!, or the Crusher data compression software by DC Micro Development
- CRUSH - An experimental file compressor by Ilya Muravyov 
CRUSH writes files to its native uncompressed .CRU archive format, then uses an external compression program, such as PKZIP, to compress the CRU file. The theory is that a single large file usually compresses better than multiple small files. CRUSH tries to order the files so as to optimize the compression ratio.
CRUSH can optionally create and use an index file (.CRI), outside of the compressed archive.
CRU and CRI files start with ASCII "
CRUSH v", and apparently have
0x0a 0x1a 0x00 at offset 10.
The 4-byte integer at offset 22 has value 26 (
1a 00 00 00) for CRI, or a generally larger value for CRU.
- CRUSH18.ZIP → MANUAL.DOC, "Technical Details" section