# sha256sum Cheatsheet - Launch Pad

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# sha256sum Cheatsheet

Quick reference for `sha256sum`, a tool to compute and verify SHA-256 checksums. SHA-256 is the common default for verifying downloads and file integrity.

## Basic usage

- `sha256sum file.img` – print SHA-256 hash and filename.
- `sha256sum file1 file2` – hash multiple files.
- `echo -n "test" | sha256sum` – hash data from stdin.

## Common options

- `-b` – read files in binary mode (default on Linux).
- `-t` – read files in text mode (mainly for non-Unix systems).
- `-c` – check SHA-256 sums from a file.

## Creating and verifying checksum files

- `sha256sum file.img > file.img.sha256` – save checksum.
- `sha256sum file1 file2 > checksums.sha256` – create checksum list.
- `sha256sum -c file.img.sha256` – verify a single file.
- `sha256sum -c checksums.sha256` – verify multiple files.

## Tips

- Publish SHA-256 hashes over HTTPS, signed release notes, or another trusted channel.
- Users should compare the hash they compute with the published hash, not just “it downloaded fine”.
- For even stronger hashes, see `sha512sum`.

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