shasum

Calculate SHA-1 hash

$ shasum [file]

$ shasum -a 256 [file]

$ shasum -a 512 [file]

$ shasum -c [checksums.txt]

$ echo -n "[text]" | shasum

$ shasum -b [file]

$ shasum -a 256 [*.tar.gz] > [SHA256SUMS]

shasum [-a algorithm] [-b] [-c] [options] [files]

shasum computes and verifies SHA message digests. SHA hashes are cryptographic fingerprints used for file integrity verification.
Algorithm selection chooses hash size. SHA-256 is commonly used for downloads and security. SHA-1 is legacy but still used in some contexts.
Check mode verifies files against recorded hashes. It reads a checksum file and confirms each listed file matches its hash.
Output format shows hash followed by filename. BSD-style output includes the algorithm name. Both formats are understood for verification.
Binary mode is recommended for non-text files. It ensures consistent hashing across platforms.
Stdin processing enables hashing command output or piped data without intermediate files.

-a ALG

Algorithm (1, 224, 256, 384, 512, 512224, 512256).

Binary mode.

Check hashes from file.

Text mode (default).

Portable mode.

Status only (with -c).

Warn about improper lines.

Exit non-zero for improperly formatted lines.

BSD-style output.

Show help.

SHA-1 is cryptographically weakened - use SHA-256+ for security. Hash verification requires original hash to be trusted.

shasum is a Perl script included with Perl. It provides a unified interface to SHA algorithms, mirroring the functionality of sha256sum and similar coreutils programs.

sha256sum(1), md5sum(1), openssl(1), b2sum(1)