[sf-lug] multisum - multipule "simultaneous" checksums

[Michael Paoli]

Mentioned at SF-LUG meeting (came up in conversation)
... multisum - I wrote some years back to more handily do
multiple checksums / secure hash calculations "simultaneously"
(all at once with a single read).
By default (but can be changed with options) it does the hashes that
Debian calculates and signs on their ISOs.
Anyway, quite handy in general for use in validating software/ISOs.

Wee bit 'o description:

multisum - compute one or more hash sums on file(s) in a single read  
pass of file(s). The --help gives a pretty good overview of its  
functionality:

$ multisum --help
multisum [options] [file ...]
     Options are case insensitive, except as noted
     --help - print this help text and exit, overrides other options
     --blocksize blocksize
     --blocksize=blocksize
     --bs blocksize
     --bs=blocksize
         set input read blocksize to blocksize, default units in bytes,
         default blocksize is 4096 bytes, the following suffix multipliers
         may be used, those ending in iB are case sensitive:
         s     - 512 byte "blocks" (sectors)
         k KiB - 2*s
         m MiB - 1024 KiB
         g GiB - 1024 MiB
         t TiB - 1024 GiB
         p PiB - 1024 TiB
         e EiB - 1024 PiB
         z ZiB - 1024 EiB
         y YiB - 1024 ZiB
     algorithms to use, by default we use these:
     MD5 SHA-1 SHA-256 SHA-512
     algorithm(s) used may be specified by options below,
     specifying any of these overrides use of the default algorithm(s):
         --md5 --md5sum - MD5
         --sha-1 --sha-1sum --sha1 --sha1sum - SHA-1
         --sha-224 --sha-224sum --sha224 --sha224sum - SHA-224
         --sha-256 --sha-256sum --sha256 --sha256sum - SHA-256
         --sha-384 --sha-384sum --sha384 --sha384sum - SHA-384
         --sha-512 --sha-512sum --sha512 --sha512sum - SHA-512
         --all --allsum --allsums - use all of the above algorithms

Anyway, it can be grabbed here:
http://www.rawbw.com/~mp/perl/multisum
See also:
http://www.rawbw.com/~mp/perl/