SHA1SUM(1)

📦
version 9.10 · 5 versions
, in ubuntu stonking

💅 SHA1SUM(1) — okay so bestie, let's talk about sha1sum ✨

hi hi hiii 🫶 you found the manual page for sha1sum, and honestly? iconic. she's a legacy queen, she's been around forever, and she still shows up to work every day. let's get into it 💖

NAME 🎀

sha1sum — compute and check SHA1 message digest. that's it, that's the whole job. no cap. ✨

SYNOPSIS 🌸

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

DESCRIPTION 🦋

so what she actually does: she prints or checks SHA1 (160-bit) checksums. she's the legacy interface to the cksum utility — like, the original, the blueprint, the blueprint-adjacent icon. 👑

and here's the vibe with the arguments: with no FILE, or when FILE is -, she reads from standard input. yes, literally - means "stdin bestie". stdin always understood the assignment. 🥰

okay, the options. here we go, don't scroll away:

  • -b, --binary — read in binary mode
  • -c, --check — read checksums from the FILEs and check them. this is the "am I being lied to?" mode 🔍
  • --tag — create a BSD-style checksum
  • -t, --text — read in text mode, and yes this is the default
  • -z, --zero — end each output line with NUL, not newline, and disable file name escaping. NUL, not newline. she's not like other girls 💀

the next five are only useful when verifying checksums 👑

okay bestie, listen, these five are specifically for the checking era of your life. if you're not verifying, they're just standing there being pretty:

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

the ~lore~ of 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 — like, she only trusts her own receipts. 💖

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. so like:

checksum *filename

or

checksum  filename

one little asterisk and suddenly everything means something. it's giving detail-oriented. 🌟

and on GNU systems? there is no difference between binary mode and text mode. none. zero. they're the same picture. 🙈

BUGS 💀

okay so this is the serious part and I need you to actually read it:

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. fr fr, protect yourself. 🔥

AUTHOR 👑

Written by Ulrich Drepper, Scott Miller, and David Madore. legends, all three. 🎀

REPORTING BUGS 😭

found something broken? tell the girlies:

SEE ALSO 🌈

💜 and that's the page, bestie

cute little sign-off real quick: this package was Packaged by Ubuntu (9.10-1ubuntu2), and the copyright reads Copyright © 2026 Free Software Foundation, Inc. 📜

the license is 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. and it says, and I quote, there is NO WARRANTY, to the extent permitted by law. 🫶

all of this is from GNU coreutils 9.10, dated August 2026. slay, go compute a checksum, ily 💖✨🎀

📦 where this page comes from