shasum
Compute and verify SHA message digests
TLDR
Calculate SHA-1 hash
SYNOPSIS
shasum [-a algorithm] [-b] [-c] [options] [files]
DESCRIPTION
shasum is a unified Perl-based utility for computing and verifying SHA message digests across all algorithm variants. The -a option selects the algorithm: SHA-1 (default), SHA-224, SHA-256, SHA-384, SHA-512, and the truncated SHA-512/224 and SHA-512/256 variants. SHA-256 is the most commonly used for software distribution verification and security applications.
In check mode (-c), shasum reads a file containing previously generated checksums and verifies each listed file against its recorded hash, reporting success or failure. Output format shows the hash followed by the filename, with BSD-style output (--tag) additionally including the algorithm name. Both formats are understood during verification.
This command is the standard SHA utility on macOS and systems with Perl installed, providing equivalent functionality to the separate sha1sum, sha256sum, and sha512sum commands found in GNU coreutils.
PARAMETERS
-a ALG
Algorithm (1, 224, 256, 384, 512, 512224, 512256).-b
Binary mode.-c, --check
Check hashes from file.-t
Text mode (default).-p
Portable mode.-s, --status
Status only (with -c).-w, --warn
Warn about improper lines.--strict
Exit non-zero for improperly formatted lines.--tag
BSD-style output.-h, --help
Show help.
CAVEATS
SHA-1 is cryptographically weakened - use SHA-256+ for security. Hash verification requires original hash to be trusted.
HISTORY
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.
