NEXTBOOT(8)

💅 NEXTBOOT(8) — like, the system manager's manual, but make it cute

okay so before we even start: this is nextboot from section 8 of the manual, aka the "system manager's manual" corner of the universe. she's a real one. let's go 🎀

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✨ NAME ✨

nextboot — the girl who sets up an alternate kernel and boot flags for your next reboot. one-shot deal, no strings attached 💖

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🦋 SYNOPSIS 🦋

nextboot [-aDf] [-e variable=value] [-k kernel] [-o options]
nextboot -D

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🌸 DESCRIPTION 🌸

so basically nextboot is your little pre-boot bestie. she lets you pick some combo of an alternate kernel, boot flags, and kernel environment for the next time the machine boots. main character energy only, no repeats 👑

here's the iconic part: once loader(8) loads in the new kernel info from the /boot/nextboot.conf file, that config is disabled. why? because if the new kernel hangs the machine, then once you reboot, the machine automatically reverts to its previous configuration. she's got your back fr fr 🫶

so like, worst case scenario you just reboot twice and you're back to normal. slay.

the flags, in order 🎀

• -a — makes nextboot append to an existing configuration in /boot/nextboot.conf. by default any existing configuration gets overwritten, so this is the "actually, keep my old stuff too" option 💅
• -D — invoking nextboot with this removes an existing nextboot configuration. it's the delete button, periodt.
• -e variable=value — adds the variable and value you give it to the kernel environment. the value gets quoted when it's written to the nextboot configuration, so no funny business with spaces 🌈
• -f — disables the sanity checking that checks if the kernel really exists before writing the nextboot configuration. it's giving "yolo, trust me". highkey only use it if you know what you're doing 💀
• -k kernel — specifies a kernel directory relative to /boot to load the kernel and any modules from.
• -o options — lets you pass kernel flags for the next boot.

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🍓 FILES 🍓

• /boot/nextboot.conf — the configuration file that the nextboot configuration is written into. that's her home. that's where she lives 🏠

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⭐ EXAMPLES ⭐

to boot the GENERIC kernel with the nextboot command:

nextboot -k GENERIC

to enable into single user mode with the normal kernel:

nextboot -o "-s" -k kernel

to remove an existing nextboot configuration:

nextboot -D

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👑 SEE ALSO 👑

boot(8), freebsd-update(8), loader(8) — go read those too, iykyk 📚

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🧚 HISTORY 🧚

the original nextboot manual page first appeared in FreeBSD 2.2. she used a very different interface to achieve similar results. glow-up, honestly.

the current incarnation of nextboot appeared in FreeBSD 5.0. that's the version you're looking at rn ✨

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💜 AUTHORS 💜

this manual page was written by Gordon Tetlow <gordon@FreeBSD.org>. give him his flowers 🌸

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🙈 BUGS 🙈

okay so the nextboot code is implemented in loader(8). and like… it is not the most thoroughly tested code. the author also says — and i quote in spirit — that it's his first attempt to write in Forth. respect the honesty ngl 😭

finally, it does some evil things, like writing to the file system before it has been checked. yes, for real. if it scrambles your file system, do not blame him. that's the actual stated policy 💀🔴

⚠️ bestie read that BUGS section again. writing to an unchecked file system is genuinely dangerous, this is not a drill, this is not a vibe check, this is a real warning 🚨

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and that's the whole page, mwah 💋 — sourced from Debian, dated December 8, 2025, NEXTBOOT(8), no cap, that's the tea 🎀