Matching filenames and file sizes are useful transfer checks, but they do not compare every byte. SHA-256 provides a practical content check for a completed file copy. Keep the source unchanged until the comparison and the receiving application's check are complete.

Compare stable copies

Close the program that is writing the source file and let the transfer finish. For a live database or virtual machine disk, use its documented export or shutdown procedure first; a checksum of changing data can be inconsistent even when the copy process itself reports no error.

On Linux, run sha256sum followed by the source file's quoted path. Run it again for the destination file, using the actual destination path. Confirm that both operations finish without read errors and that the displayed filenames correspond to the intended pair.

Compare the complete digest, not just its beginning or ending. Matching SHA-256 values provide strong evidence that those file contents are identical. A different value means the files need investigation; check whether you compared the correct versions and whether either changed during the test before repeating the transfer.

Keep the scope of the result clear

The checksum describes file content, not its name, owner, permissions or application compatibility. A matching document can still need its associated files, fonts or database settings to work on another computer. Open the transferred copy in the intended application and inspect a known record or section as a separate acceptance check.

When a sender supplies a checksum manifest, sha256sum --check can verify its listed files. Review missing-file and mismatch messages; options that suppress output or ignore missing entries can conceal information needed for a handover.

A checksum obtained from the same untrusted download location does not independently establish the publisher's identity. For this transfer task, retain the source and destination paths, completed comparison and application result together. Only then consider retiring the original copy according to your wider data-retention plan.

Sources: Ubuntu documentation.