sha1sum
Compute and verify SHA-1 checksums
TLDR
SYNOPSIS
sha1sum [OPTION]... [FILE]...
DESCRIPTION
sha1sum computes and verifies SHA1 (160-bit) message digests as described in FIPS-180-1. It generates a unique 40-character hexadecimal hash for file contents, useful for verifying file integrity and detecting modifications.With no FILE argument or when FILE is -, sha1sum reads from standard input. Output format is: checksum, space, mode indicator (* for binary, space for text), and filename.When checking with -c, input should be previous sha1sum output. Each line is verified and reported as OK or FAILED.
PARAMETERS
-b, --binary
Read in binary mode-c, --check
Read checksums from FILEs and verify them-t, --text
Read in text mode (default)--tag
Create a BSD-style checksum output-z, --zero
End each output line with NUL instead of newline--ignore-missing
Don't fail for missing files when checking--quiet
Don't print OK for each successfully verified file--status
Don't output anything; use exit status for result--strict
Exit non-zero for improperly formatted checksum lines-w, --warn
Warn about improperly formatted checksum lines
CAVEATS
SHA-1 is cryptographically broken and vulnerable to collision attacks. It should not be used for security-sensitive applications like digital signatures. For stronger security, use sha256sum or sha512sum instead.
HISTORY
sha1sum is part of GNU coreutils, written by Ulrich Drepper, Scott Miller, and David Madore. SHA-1 was designed by the NSA and published by NIST in 1995. Collision vulnerabilities were demonstrated in 2017, leading to deprecation for cryptographic purposes.
