ESI(8)

💖 ESI(8) 💖

okay bestie, buckle up, we're doing maintenance commands today and this one is lowkey iconic — it's esi, from the esi manual page, and it's all about the end system identifier. let's get into it 🦋

✨ NAME ✨

esi — get or set the end system identifier (ESI)

🌸 SYNOPSIS 🌸

esi [itf]
esi [-f] esi [itf]
esi -V

💅 DESCRIPTION 💅

so like, esi shows you or sets the end system identifier — the ESI — of an ATM interface. and what even is an ESI? it's a unique six-byte number that corresponds to the MAC address of LAN technologies like Ethernet. yes bestie, six bytes of pure identity ✨

if you leave out the interface number itf, it just defaults to interface 0. no biggie. and the esi argument? it's a string of twelve hex digits. twelve. count 'em 💅

🫶 important lil heads up: only the ESI stored in the kernel is accessed here. esi does not change the ESI stored on the NIC. the NIC keeps its own vibe, untouched.

also — if a non-zero ESI is already set on an interface, you have to use the -f option to overwrite it. no sneaky overrides, the tool will simply not let you 🙈

and one more thing that's genuinely important, not just me being dramatic: ESI changes are not automatically propagated throughout the system, e.g. to ilmid. so esi should be used early during system initialization. like, before everything else wakes up. timing matters, periodt 👑

🎀 OPTIONS 🎀

• -f — force overwriting an existing ESI. use it when something's already there and you need it gone 💅
• -V — print the version number of esi on standard output and exit. quick lil flex, then it dips ✨

👑 AUTHOR 👑

Werner Almesberger, EPFL ICA <Werner.Almesberger@epfl.ch>

🌈 SEE ALSO 🌈

ilmid(8)

and that's the whole page bestie, no cap. this one's from the Linux manual, dated April 26, 2000 — Maintenance Commands energy all the way through. go set an ESI responsibly, early in init, and hydrate 💜🧚‍♀️