ISOSIZE(8)

👑 ISOSIZE(8) 👑 — it's the isosize page from section 8 of the manual, bestie (system administration girlies rise up)

---

🌸 NAME 🌸

isosize — bestie, all it does is output the length of an iso9660 filesystem. That's it. That's the whole job. And it ate. 💅

---

✨ SYNOPSIS ✨

isosize [options] iso9660_image_file

---

🦋 DESCRIPTION 🦋

Okay so picture this: you've got a file. Inside that file there is an iso9660 filesystem, just vibing in there. This command tells you how long that filesystem is. Periodt.

That file can be a totally normal regular file, or it can be a block device — like /dev/hdd or /dev/sr0, iykyk. 💖

And here's the tea: if you give it no options and nothing goes wrong, it just prints the size of the iso9660 filesystem in bytes. And ngl, that number can get HUGE — we're talking >> 4 GB huge. Like, main character energy numbers. 😭

---

💅 OPTIONS 💅

• -x, --sectors — shows the block count and the block size in a human-readable form. And the way it does this? It calls blocks "sectors" instead. Just... terminology. Iconic of it, honestly. ✨
• -d, --divisor number — bestie, this one only does anything when -x is NOT given. What it shows (if there are no errors) is the iso9660 file size in bytes divided by number. So if number happens to be the block size, then the value you get is the block count. Math girlies, we love to see it. 🧚

So here's why that matters, fr fr: the size of the file (or block device) that's holding an iso9660 filesystem can be a little bit bigger than the actual size of the iso9660 filesystem itself. One reason? CD writers are allowed to tack "run out" sectors onto the end of an iso9660 image. Rude of them but okay. 🙈

• -h, --help — shows you the help text and then dips. 👋
• -V, --version — shows you the version and then dips. 👑

---

🔥 EXIT STATUS 🔥

• 0 — success, we slayed 🎀
• 1 — generic failure, like an invalid usage situation. not the vibe 💀
• 32 — all failed 😭
• 64 — some failed 🫶

---

🐛 REPORTING BUGS 🐛

Found a bug? Don't suffer in silence, bestie. Take it to the issue tracker:

https://github.com/util-linux/util-linux/issues

---

🌈 AVAILABILITY 🌈

The isosize command is part of the util-linux package, which you can download from the Linux Kernel Archive:

https://www.kernel.org/pub/linux/utils/util-linux/

---

Okay that's the whole page, you're officially an isosize expert now, no cap. 💖

This lil beauty is from util-linux 2.42.4, dated 2026-09-21 — mwah, go forth and measure your iso9660 filesystems, queen. 🎀✨👑