proc_sys(5)

💖 proc_sys(5) — bestie's guide to /proc/sys/ 💖

okay so like. this is proc_sys, a file formats manual page, and it's lowkey one of the most iconic little corners of your Linux box. pull up a chair 🫶

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✨ NAME ✨

/proc/sys/ — system information, and sysctl pseudo-filesystem

🌸 DESCRIPTION 🌸

🎀 /proc/sys/

this directory has been serving looks since Linux 1.3.57 (yes, literally that long, main character energy since forever 💅). inside it you'll find a whole bunch of files and subdirectories, and they correspond to kernel variables. the way that kernel variables just live in a folder?? obsessed.

these variables can be read, and in some cases modified, using the /proc filesystem, and also using the (deprecated!!) sysctl(2) system call.

⚠️ okay bestie real talk: sysctl(2) is deprecated. go through /proc instead, fr fr. don't be texting your ex.

🧚 the formatting rules, don't skip these

• String values may be terminated by either '\0' or '\n'. either one, she's flexible 💖
• Integer and long values may be written either in decimal or in hexadecimal notation (e.g., 0x3FFF). yes hex girlies, we see you ✨
• When you're writing multiple integer or long values, you can separate them with any of these whitespace characters: ' ', '\t', or '\n'.
• Using any other separators leads to the error EINVAL. that's a vibe check failure, sorry 😭

🦋 see also (the little sibling pages)

these all got their own pages and honestly they ate:

• proc_sys_abi(5)
• proc_sys_debug(5)
• proc_sys_dev(5)
• proc_sys_fs(5)
• proc_sys_kernel(5)
• proc_sys_net(5)
• proc_sys_net_ipv4(5)
• proc_sys_proc(5)
• proc_sys_sunrpc(5)
• proc_sys_user(5)
• proc_sys_vm(5)

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👑 SEE ALSO 👑

• proc(5)

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and that's the whole page, bestie, you're basically a kernel whisperer now 🐚💜

this was Linux man-pages 6.20, dated 2026-02-08 — mwah, go read some variables 🌈⭐🎀