Command library / sha256sum

Compute or verify SHA-256 file checksums

Prints the SHA-256 hash of one or more files — a fingerprint that changes if even one byte does. Use it to confirm a download wasn't corrupted or tampered with, to verify a whole set of files against a checksums list with -c, or to prove forensic evidence hasn't changed since it was collected.

Usage

Options and flags

• file

  file to hash, or a checksums file when used with -c

• -c, --check

  read hashes from a file and verify each one against the actual file

• --quiet

  with -c: only print files that FAILED verification

• --tag

  print in BSD-style tagged format: SHA256 (file) = hash

• -b, --binary

  read files in binary mode (default on Windows/WSL, irrelevant on Linux text mode)

Examples

• sha256sum firmware.bin

  Print the hash of one file — compare it by eye against a known-good value.

• sha256sum -c checksums.txt

  Verify every file listed in checksums.txt — prints OK or FAILED for each.

• sha256sum --tag readme.txt

  BSD-style output: SHA256 (readme.txt) = <hash>.

• sha256sum evidence1.img evidence2.img

  Hash two pieces of evidence in one pass, for the case file.

Common mistakes

Related commands