asum - The fastest MD5 checksum tool.

Usage:
1> asum ? 
FILES/M,ALL/S,TO/K,CHECK/K: 

FILES: Files to checksum, if directories are supplied, the contained files
       will be checksummed. AmigaDOS patterns can be used.
ALL:   Traverse directories recursively.
TO:    Output the generated list of checksums to this file, instead of the
       standard output.
CHECK: Validate this previously generated list of checksums.

Examples:
1> asum C:Dir C:List 
f422ffbea14e31c2073a16134f781ca2  C:Dir
3a36df1e3f39018bb0f6b4232d6a5aba  C:List

1> asum S:#?-Startup 
c23e2afc5cea3b09bc2dcb890b441a3a  S:Network-Startup
17ab20b698004d01f1197c4e9f27ec51  S:User-Startup
e979a38b5f13a3fb8a8e67d0d3873547  S:Shell-startup
14fa4c0562f540a9d250365eb5d65818  S:Network-User-Startup
d5cae30fc54900a314dd2c6cf2175825  S:WHDLoad-Startup

1> asum S: TO=RAM:checkfile
1> echo "" >>S:User-Startup
1> asum CHECK=RAM:checkfile
S:User-Startup: MD5 mismatch!
1> echo $RC
10

Relevant information:
Uses the awesome MD5 code from HippoPlayer, which is why it is so fast,
thank you K-P!