SHA

SHA Checksums

Verify file integrity with a cryptographic hash.

# Single file
shasum -a 256 file.iso              # SHA-256
shasum -a 256 -c file.iso.sha256    # verify against a checksum file
 
# Deterministic checksum for an ENTIRE directory's contents
find . -type f -print0 | sort -z | xargs -0 shasum | awk '{ print $1 }' | shasum

macOS

shasum ships with macOS; sha256sum (GNU) does not unless you brew install coreutils (then gsha256sum). The directory recipe sorts first so the result is stable regardless of filesystem order.