SHA1SUM(1)

📦
version 9.12 · 24 versions
, in arch rolling

✨ SHA1SUM(1) ✨

okay bestie, pull up a chair because we're talking about sha1sum, a User Commands girly from the GNU coreutils house 💖 this is the manual page for her, and yes she is iconic, yes she is legacy, yes she still eats.

💅 NAME 💅

sha1sum — compute and check SHA1 message digest 🦋

🌸 SYNOPSIS 🌸

sha1sum [OPTION]... [FILE]...

✨ DESCRIPTION ✨

So basically she prints or checks SHA1 (160-bit) checksums. That's the whole gig. She's the legacy interface to the cksum(1) utility, meaning she's the OG cousin and cksum is the new main character, but we still love her fr fr.

If you give her no FILE, or if FILE is literally just -, she reads from standard input. no notes, that's just how she rolls 🫶

🎀 OPTIONS 🎀

  • -b, --binary — read in binary mode
  • -c, --check — read checksums from the FILEs and check them
  • --tag — create a BSD-style checksum
  • -t, --text — read in text mode (this is the default, bestie)
  • -z, --zero — end each output line with NUL, not newline, and disable file name escaping

🌈 the five options that only matter when you're verifying checksums 🌈

these five are lowkey useless unless you're in check mode, iykyk:

  • --ignore-missing — don't fail or report status for missing files
  • --quiet — don't print OK for each successfully verified file
  • --status — don't output anything, status code shows success
  • --strict — exit non-zero for improperly formatted checksum lines
  • -w, --warn — warn about improperly formatted checksum lines

💖 the lil helper options 💖

  • --help — display this help and exit
  • --version — output version information and exit

🧚 THE TEA ON HOW THE SUMS WORK 🧚

The sums are computed as described in FIPS-180-1. When checking, the input should be a former output of this program. The default mode is to print a line with: checksum, a space, a character indicating input mode ('*' for binary, ' ' for text or where binary is insignificant), and name for each FILE.

and here's the gag: there is no difference between binary mode and text mode on GNU systems. so all that -b vs -t drama? on GNU it's giving absolutely nothing 💀

💀 BUGS 💀

Do not use the MD5 algorithm for security related purposes. Instead, use an SHA-2, SHA-3, or BLAKE2 algorithm, implemented in the cksum(1) program. like seriously bestie, MD5 for security is not the vibe, that's a whole red flag 🚩

👑 AUTHOR 👑

Written by Ulrich Drepper, Scott Miller, and David Madore. legends only, no cap.

📢 REPORTING BUGS 📢

Found a bug? tell the girlies:

Copyright © 2026 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>.

This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law.

🦋 SEE ALSO 🦋

Full documentation <https://www.gnu.org/software/coreutils/sha1sum> or available locally via: info '(coreutils) sha1sum invocation'

GNU coreutils 9.12 — September 2026 🌸 and that's the whole page bestie, mwah, go checksum something and stay hydrated 💖✨🎀

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