PEAZIP FREE ARCHIVER
PEAZIP FOR WINDOWS PEAZIP FOR WINDOWS 64 BIT PEAZIP PORTABLE PEAZIP LINUX / BSD archival tool  freeware zipper  zipping app  manage 7z rar tar zip files

LEARN MORE  |  CHANGELOG  |  PROGRAM SCREENSHOTS  |  FILE COMPRESSION BENCHMARKS  |  SOFTWARE REVIEWS  |  UNACE UNRAR ADD-ONS  |  ONLINE HELP  |  FAQ  |  DONATIONS
 

PEAZIP FREE ARCHIVER > FREQUENTLY ASKED QUESTIONS > FILE MANAGER > DETECT IDENTICAL DATA

HOW TO FIND DUPLICATE FILES

DETECT REDUNDANT FILES WITH IDENTICAL CHECKSUM / HASH VALUE

MORE INFORMATION ABOUT DUPLICATE DATA DETECTION

duplicate data detection



Search for duplicate files


When browsing a filesystem the file browser can show file checksum / hash value on demand in last column, allowing to identify binary identical files which have same checksum/hash value.
Clicking the name of the function (in context menu, "File tools" group) will display hash or checksum value for all (or selected) files.
Clicking "Find duplicates" will display size and hash or checksum value only for duplicate files - same binary identical content featured in two or more distinct files - and report the number of non-unique files identified.

In both cases, sorting for CRC column allows to group all files (in same folder, or same search filter) with identical hash or checksum.

The verification function can be set in main application's menu: Organize, Browser, Checksum/hash), a wide selection of algorithms can be selected, ranging from simple checksum functions as Adler32, CRC family (CRC16/24/32, and CRC64) to hash functions like eDonkey/eMule, MD4, MD5, and cryptographically strong hash as Ripemd160, SHA-1 and SHA-2 (SHA224/256/384, and SHA512), and Whirlpool512.

When browsing an archive this on demand verification is not available, but some archive types provides the same integrity-checking information, saving for each archived object the pre-computed checksum or hash value depending on the archive format, and on the archival settings employed - i.e. CRC32 in ZIP archives - allowing to sort archive content by CRC column to group identical files and find out duplicates.


Find similar images


When browsing a filesystem, PeaZip can display image thumbnails: context menu, organize, check show picture thumbnails, or select a file browser's preset style showing thumbnails.
While checksum/hash based inspection allows to find exactly identical files (and images), thumbnails allows the user to find similar images (i.e. same picture or graphic saved in different formats, or with different color depth or compression settings, or scaled to different sizes), to help in deciding if the (pseudo)duplication is acceptable, and what copy to keep.


Verify multiple checksum and hash values at once


Check files utility in "File tools" submenu (context menu) allows to compare multiple hash and checksum algorithms of multiple files at onceEmploying multiple functions, and relying on cryptographically strong hash algorithms as Ripemd, SHA-2, Whirlpool, can identify even malicious attempt of forging identical-looking files.


Alternative method: byte-to-byte comparison


Compare files utility in "File tools" submenu performs byte to byte comparison between two files; unlike checksum/hash method it is not subject of collisions under any circumstance, and can report what the different bytes are - so it not only tells if two files are not identical, but also what changes were made between the two versions.
More information about duplicate data detection

External online resources: definitions of checksumWikipedia validate data integrity, and hash functionsfind hash value on Wikipedia.

Topics and serach suggestions: how to find duplicate files on Microsoft Windows and Linux systems, compare and deduplicate content, detect redundant data, remove identical files wiki, calculate checksum algorithm, compute hash value, FIPS, identify similar images, seemingly identical files, find multiple copies of a file.
RELATED & SIMILAR PAGES
7-ZIP FILE MANAGER
BACKUP FILES & FOLDERS

CONVERT ZIP FORMAT

DATA ENCRYPTION
 
EXTRACT BZ2 FORMAT

EXTRACT GZ FORMAT

EXTRACT TAR FILES

HOW TO ZIP UNZIP FILES

MANAGE ISO IMAGE FILES

MICROSOFT CAB FORMAT
OPEN ACE FILES
OPEN RAR ARCHIVES

OPTIMIZE COMPRESSION

PROTECT FROM DELETION
 
READ ENCRYPTED FILE

REDUCE BACKUP SIZE

SPLIT EMAIL ATTACHMENT

WIPE DATA

ZIPX FILE EXTRACTION







DOWNLOADS
free rar archiver
All PeaZip downloads
PeaZip for Windows
PeaZip for Windows 64 bit
PeaZip Portable
PeaZip Linux/BSD

SUPPORT
how do i zip unzip files
More information
Online help
Frequently Asked Questions





DONATE
how to manage rar archive
Support PeaZip project, or donate to FAO, UNICEF and UNESCO from donation page

© PeaZip srl: TOS, Privacy

Developer detect duplicate data
PeaZip Wiki (GitHub)
find duplicate data
Releases Feed find duplicate files