Learn to compute and verify SHA-256 checksums from the command line to ensure file integrity. 16.11.2025 | reading time: 2 min When he downloads an installer or moves an archive between systems, how can he prove the bits arrived intact? The sha256sum utility computes SHA-256 hashes so he can compare digests, detect corruption, and validate authenticity. Check a download quickly Download verification in action: create a checksum file and verify it. ```bash sha256sum example.iso > example.iso.sha256 # contents of example.iso.sha256 "e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855 example.iso" sha256sum -c example.iso.sha256 example.iso: OK # simulate tamper printf "x" >> example.iso sha256sum -c example.iso.sha256 example.iso: FAILED sha256sum: WARNING: 1 computed checksum did NOT match ``` Beyond the basic check Use `sha256sum -c` to batch-verify checksum files, `-b` to force binary mode, and `--tag` to create BSD-style lines when needed; combine `find` and `xargs` to compute checksums for many files and use `--status` in scripts to act only on success or failure. Tools that complement checksums Checksums prove integrity but not provenance: use GPG to sign checksum files so he can verify who generated them, use OpenSSL or `sha512sum` for different algorithms, and consider GUI tools like GtkHash for desktop workflows. Finish line A single `sha256sum` check can prevent wasted time and security incidents; to broaden command-line skills and prepare for certification consider CompTIA Linux+ or LPIC-1 and intensive exam preparation at bitsandbytes.academy. Join Bits & Bytes Academy First class LINUX exam preparation. security utilities backup
