JLS(8)

💅 JLS(8) — the jls girlies' guide to listing jails 👑

okay so bestie, welcome to jls — it's the jls(8) utility, it lives in the System Manager's Manual, and it is literally the main character of jail-wrangling. let's get into it 🫶

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✨ SYNOPSIS ✨

jls [--libxo] [-dhNnqsv] [-j jail] [parameter ...]
jls -c [-d] -j jail

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🌸 DESCRIPTION 🌸

The jls utility lists all active jails, or the specified jail. each jail is represented by space-separated values of the listed parameters, one jail per line (unless the parameters themselves contain newlines — yes, that's a real caveat, keep it in mind 🙈).

the pseudo-parameter all will show all available jail parameters. and if you wanna know what parameters even exist in the first place? you grab that list via sysctl -d security.jail.param. and for a description of some core parameters, go see jail(8) — iykyk.

if no parameters or any of the options -chns are given, the following four columns will be printed:

1. jail identifier (jid)
2. IP address (ip4.addr)
3. hostname (host.hostname)
4. path (path)

🚨 okay -c mode is different: when the -c option is used, jls will not emit any output except for usage errors. this mode is intended solely to check for a single jail's existence, and it does not accept any parameter or print-option flags. no flags, no parameters, none. we respect the boundaries 💅

the following options are available:

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🎀 OPTIONS 🎀

• --libxo — generate output via libxo(3) in a selection of different human and machine readable formats ✨ see xo_options(7) for details on command line arguments.
• -c — only check for the jail's existence. that's it, that's the whole job 👑
• -d — list dying as well as active jails 💀 (yes, jails can be dying, don't make it weird)
• -h — print a header line containing the parameters listed. if no parameters are given on the command line, all is assumed 🎀
• -N — in the standard display mode, print each jail's name instead of its numeric ID. if the jail does not have a name, the numeric ID is printed instead. no name? no problem 🫶
• -n — print parameters in name=value format, where each parameter is preceded by its name. if no parameters are given on the command line, all is assumed 🌈
• -q — put quotes around parameters if they contain spaces or quotes, or are the empty string. safety first, bestie 🎀
• -s — print parameters suitable for passing to jail(8), skipping read-only and unused parameters. implies -nq ⭐
• -v — extend the standard display with a multiple-line summary per jail, containing the following parameters: jail identifier (jid), hostname (host.hostname), path (path), jail name (name), jail state (dying), cpuset ID (cpuset), IP address(es) (ip4.addr and ip6.addr) 🔥 so much info, we love a detailed queen
• -j jail — the jid or name of the jail to list. without this option, all active jails will be listed 🌸

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🦋 SEE ALSO 🦋

jail_get(2), libxo(3), xo_options(7), jail(8), jexec(8)

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💜 HISTORY 💜

The jls utility was added in FreeBSD 5.1. Extensible jail parameters were introduced in FreeBSD 8.0. libxo support was added in FreeBSD 11.0. a whole glow-up timeline fr fr ✨

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and that's the page bestie 💖 this iconic little number is from the Debian flavour of things, dated July 25, 2025, and it's filed under JLS(8) — go list some jails, you're gonna slay 🎀👑