sysfs(5)

💖 sysfs(5) — the filesystem that lets you peek at kernel objects 💖

okay bestie, sit down, hydrate, because this is the sysfs manual page from section 5 of the File Formats Manual and it's genuinely iconic. it's short, it's sweet, and it's the reason /sys exists at all. 🫶

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✨ NAME ✨

sysfs — a filesystem for exporting kernel objects 🌈

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🌸 DESCRIPTION 🌸

so the sysfs filesystem is a pseudo-filesystem that gives you an interface to kernel data structures 💅. (and like, more precisely: the files and directories in sysfs give you a view of the kobject structures that are defined internally inside the kernel.) the files under sysfs spill the tea about devices, kernel modules, filesystems, and other kernel components 👑

sysfs is commonly mounted at /sys. typically the system mounts it automatically for you (slay), but you can also mount it manually with a command like:

mount -t sysfs sysfs /sys

a lot of the files in sysfs are read-only, but some are writable, which means you can actually change kernel variables through them 😳. and to avoid redundancy, symbolic links are heavily used to connect entries across the filesystem tree — it's giving spiderweb, it's giving interconnected main character energy 🕸️✨.

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🎀 FILES 🎀

here's the rundown of some of the files and directories under the /sys hierarchy 🌸

• /sys/block/ — see sys_block(5).
• /sys/bus/ — see sys_bus(5).
• /sys/class/ — see sys_class(5).
• /sys/dev/ — see sys_dev(5).
• /sys/devices/ — see sys_devices(5).
• /sys/firmware/ — see sys_firmware(5).
• /sys/fs/ — see sys_fs(5).
• /sys/hypervisor/ — see sys_hypervisor(5).
• /sys/kernel/ — see sys_kernel(5).
• /sys/module/ — see sys_module(5).
• /sys/power/ — see sys_power(5).

every single one of them has its own page, so go read them, i'm not doing the homework for you bestie 😌

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💜 STANDARDS 💜

Linux. that's it, that's the standard. periodt. 💅

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🦋 HISTORY 🦋

Linux 2.6.0. vintage but make it modern ✨

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⚠️ NOTES ⚠️

ngl, this manual page is incomplete, possibly inaccurate, and is the kind of thing that needs to be updated very often. she's a work in progress, your honor 😭

fr fr — don't treat this one as gospel, it moves fast.

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👑 SEE ALSO 👑

• proc(5), udev(7)
• P. Mochel (2005). The sysfs filesystem. Proceedings of the 2005 Ottawa Linux Symposium.
• the kernel source file Documentation/filesystems/sysfs.rst and various other files in Documentation/ABI and Documentation/*/sysfs.rst.

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and that's the whole vibe 💖 this page came from Linux man-pages 6.20, dated 2026-09-09 — so if 6.20 is your version, you're reading the freshest lore available. go forth and ls /sys, bestie, you're literally so good at this 🌟🍓🧚