GRUB-FSTEST(1)

📦
version 2.12 · 14 versions
, in ubuntu noble

🦋 NAME 🦋

okay so bestie, listen up — grub-fstest is the debug tool for GRUB filesystem drivers. that's it, that's the whole vibe. it's the little goblin-mode utility you pull out when you need to peek inside filesystems the way GRUB sees them 💅

✨ SYNOPSIS ✨

grub-fstest [OPTION...] IMAGE_PATH COMMANDS

like, image path first, then your commands, then your options wherever they fit. slay 🎀

💖 DESCRIPTION 💖

it's a debug tool for filesystem driver. literally that's the official energy — you point it at an image and it lets you poke around inside with the commands below. no cap, this is the toolbox 🔥

🌸 Commands 🌸

  • blocklist FILE — displays the blocklist of FILE. it's giving "where does this file actually live on disk" energy 👑
  • cat FILE — copies FILE straight to standard output. classic cat behaviour, no notes 🐱
  • cmp FILE LOCAL — compares FILE (inside the image) with the local file LOCAL. vibe check between two files 💫
  • cp FILE LOCAL — copies FILE out to the local file LOCAL. extraction time 🫶
  • crc FILE — gets the crc32 checksum of FILE. numbers go brrr ⭐
  • hex FILE — shows the contents of FILE in hex. raw bytes, main character energy 💀
  • ls PATH — lists files in PATH. the og directory peek 🙈
  • xnu_uuid DEVICE — computes the XNU UUID of the device. yes it's a real thing, don't come for me 🍓

🧚 Options 🧚

  • -c, --diskcount=NUM — specify the number of input files. tell it how many disks you're juggling 🎀
  • -C, --crypto — mount crypto devices. unlocking the secret lore 🔐
  • -d, --debug=STRING — set the debug environment variable. hand it a STRING and let the logs cook 🌈
  • -K, --zfs-key=FILE|prompt — load the zfs crypto key. give it a FILE, or literally just the word prompt and it'll ask you 💜
  • -n, --length=NUM — handle NUM bytes in the output file. not more, not less, exactly NUM bestie ✨
  • -r, --root=DEVICE_NAME — set the root device to DEVICE_NAME. pick your main character 👑
  • -s, --skip=NUM — skip NUM bytes from the output file. we're jumping ahead 💅
  • -u, --uncompress — uncompress data. zip zap, make it readable 🦋
  • -v, --verbose — print verbose messages. yapping mode: enabled 😭
  • -?, --help — give this help list. when in doubt, ask for help fr fr 🌸
  • --usage — give a short usage message. the tl;dr version 🎀
  • -V, --version — print program version. receipts, we love them 🧾
⚠️ important caveat bestie: mandatory or optional arguments to long options are also mandatory or optional for any corresponding short options. so like, don't think the short versions play by different rules — they don't 💀

🌈 SEE ALSO 🌈

the full documentation for grub-fstest is maintained as a Texinfo manual. if the info and grub-fstest programs are properly installed at your site, the command

info grub-fstest

should give you access to the complete manual. obsessed 🫶

and that's the whole page, diva 💖 — this beauty is from GRUB 2.12-1ubuntu7.3, dated March 2025. go forth and debug your filesystems, no cap ⭐👑

📦 where this page comes from