cksum
TLDR
Calculate checksum of file
$ cksum [file.txt]
Calculate checksum of multiple files$ cksum [file1] [file2]
Calculate from stdin$ echo "data" | cksum
Use SHA256 algorithm$ cksum --algorithm sha256 [file.txt]
Verify checksums from file$ cksum -c [checksums.txt]
Output in base64$ cksum --base64 [file.txt]
SYNOPSIS
cksum [option]... [file]...
DESCRIPTION
cksum prints CRC checksum and byte count for files. By default uses 32-bit CRC algorithm. Part of GNU coreutils. Used to verify file integrity after transfers.
PARAMETERS
-a, --algorithm name
Select algorithm (crc, md5, sha1, sha256, sha512, etc.)-c, --check
Read checksums and verify them-l, --length bits
Digest length in bits--base64
Output base64-encoded digest--raw
Output raw binary digest--tag
BSD-style checksum (default)--untagged
Reversed style without digest type-z, --zero
End lines with NUL instead of newline--ignore-missing
Don't fail for missing files during check--quiet
Don't print OK for verified files--status
Silent mode, exit code shows result-w, --warn
Warn about malformed checksum lines
OUTPUT FORMAT
$ checksum byte_count filename
CAVEATS
CRC32 is not cryptographically secure. Use SHA256 or stronger for security-critical verification. Reads stdin when no file given or file is -.
