Print FastCDC rolling hash chunks and checksums.
usage: chunksum [-h] [-n ALG_NAME] [-f CHUNKSUMS_FILE] [-i INCR_FILE] [-m]
[path ...]
Print FastCDC rolling hash chunks and checksums.
positional arguments:
path path to compute chunksums
optional arguments:
-h, --help show this help message and exit
-n ALG_NAME, --alg-name ALG_NAME
chunksum algorithm name.
-f CHUNKSUMS_FILE, --chunksums-file CHUNKSUMS_FILE
chunksum file path, `-' for standard output.
-i INCR_FILE, --incr-file INCR_FILE
incremental updates file path
-m, --multi-process same number of multi-processes as cpu
alg-name:
Format "fc[k|m|g][0-9][sha2|blake2b|blake2s][32]".
For example, "fck4sha2", means using FastCDC("fc") with an
average chunk size of 2**8=256KB("k8") and using sha256("sha2")
to calculate the checksum.
"fcm4blake2b32" means using FastCDC with an average chunk size
of 2**4=16MB("m4") and using "blake2b" to calculate and output
a checksum of length "32" bytes(save storage).
For large files, you may using large chunk size, such as "m4",
to reduce the number of chunks.
(default: fck4sha2)
chunksums-file and incr-file:
You can specify the previous chunksums file if you want to
resume a previous check, or if you want to find the incremental
updates (new files) of the directory.
Examples:
$ chunksum /etc > ~/etc.chunksums
$ chunksum -n fcm4blake2b32 -m ~/Videos
$ chunksum -n fcm4blake2b32 -f ~/Videos/chunksums ~/Videos
$ chunksum -n fcm4blake2b32 -f ~/chunksums -i ~/chunksums.incr ~/Videos