Example usage of cksum to calculate CRC checksum and byte counts of a file
Operating system
Unix, Unix-like
Platform
Cross-platform
Type
Command
cksum is a command in Unix and Unix-like operating systems that generates a checksum value for a file or stream of data. The cksum command reads each file given in its arguments, or standard input if no arguments are provided, and outputs the file's 32-bit cyclic redundancy check (CRC) checksum and byte count.[1] The CRC output by cksum is different from the CRC-32 used in zip, PNG and zlib.[2]
The cksum command can be used to verify that files transferred by unreliable means arrived intact.[1] However, the CRC checksum calculated by the cksum command is not cryptographically secure: While it guards against accidental corruption (it is unlikely that the corrupted data will have the same checksum as the intended data), it is not difficult for an attacker to deliberately corrupt the file in a specific way that its checksum is unchanged. Unix-like systems typically include other commands for cryptographically secure checksums, such as sha256sum.
The command is available as a separate package for Microsoft Windows as part of the UnxUtils collection of native Win32 ports of common GNU Unix-like utilities.[3]
Latest GNU Coreutils cksum provides additional checksum algorithms via -a option, as an extension beyond POSIX.[1]
cksum is a command in Unix and Unix-like operating systems that generates a checksum value for a file or stream of data. The cksum command reads each file...
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Archived from the original on 7 April 2018. Retrieved 19 January 2018. "cksum". pubs.opengroup.org. Archived from the original on 18 July 2018. Retrieved...
Archived from the original on 1 January 2023. Retrieved 31 December 2013. cksum misc/4.2.04.tiff 4014024639 Gonzalez, Rafael C.; Woods, Richard E. (2002)...
algorithm is useless on a security perspective, and is weaker than the CRC-32 cksum for error detection. The main part of this algorithm is simply adding up...
features. Additionally, FreeBSD offers the Skein family of message digests. cksum md5sum md5deep GNU Core Utilities "b2sum source code in GNU coreutils"....
— Change your login shell. chvt — Change to virtual terminal number N. cksum — For each file, output crc32 checksum value, length and name of file. clear...
standard output cat Concatenates and prints files on the standard output cksum Checksums (IEEE Ethernet CRC-32) and count the bytes in a file. Supersedes...
change which users can write to a file. cksum — generates a checksum value for a file or stream of data. The cksum command reads each file given in its arguments...
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