Test a Zip Archive's Integrity Before Extracting
Check every file inside a .zip against its CRC checksum without extracting anything.
Run unzip -t big-archive.zip; it verifies each entry and ends with 'No errors detected' or lists the damaged files.
01Command
Command
$ unzip -t big-archive.zip02What it does
-t runs the same CRC32 verification that extraction performs but writes nothing to disk, so it is safe and fast for diagnosing a suspicious archive. It catches truncated downloads (the central directory is missing), damaged media (a specific member fails CRC), and password-protected archives will prompt for a password during the test.
03Risk
!Warning: It cannot repair anything — if the test fails you still need to re-download or restore from backup; a good companion is unzip -l to list contents first.
04Undo
✓No undo needed — this command does not change persistent state.
05Sources
- unzip(1) man pageEvidence: The unzip man page describes -t as testing the archive: each file is extracted in memory only to verify correctness, with a 'No errors detected' summary.
- unzip - Extract, List or Test ZIP ArchivesEvidence: Documents the -t option: test archive files, checking each file's CRC against the archive without writing anything to disk.
Last verified: 2026-09-19 · Category: Files & Folders