README for go-hash

What is this?

Pure go tool for calculating and verifying hashes of files & dirs.

It exploits concurrency where possible and uses mmap(2) for hashing/verifying files.

The hash output can be saved in a file for future verification.

How do I build it?

You need a modern go toolchain (go 1.17+):

git clone https://github.com/opencoff/go-hash
cd go-hash
make

The binary will be in ./bin/$HOSTOS-$ARCH/ghash. where $HOSTOS is the host OS where you are building (e.g., openbsd) and $ARCH is the CPU architecture (e.g., amd64).

How do I use it?

Usage:

ghash [options] file|dir [file|dir ..]

Options:
  -h, --help            Show help and exit
  -V, --version         Show version info and exit
  -r, --recurse	        Recursively traverse directories
  -x, --one-filesystem  Don't cross file system boundaries
  -L, --follow-symlinks Follow symbolic links
  -H, --hash=H		Use hash algorithm 'H' [sha256]
  --list-hashes		List supported hash algorithms
  -v, --verify-from=F   Verify the hashes in file 'F' [stdin]
  -o, --output=O        Write output hashes to file 'O' [stdout]

Hashing individual files

ghash file1 file2 file3

Hashing recursively multiple files and dirs

ghash -r dir1 dir2 file3 file4

Verifying previously generated hashes

# first generate and save the hashes
ghash -L -x -H blake3 -o /tmp/etc.ghash -r /etc

# now verify the saved hashes in /tmp/etc.ghash
ghash -v /tmp/etc.ghash

Licensing Terms

The tool and code is licensed under the terms of the GNU Public License v2.0 (strictly v2.0). If you need a commercial license or a different license, please get in touch with me.

See the file LICENSE.md for the full terms of the license.

Author

Sudhi Herle sw@herle.net