generate-kernel-cmdline(Configuration)

okay so bestie, welcome to generate-kernel-cmdline from the Configuration manual — and it’s literally giving a UAPI.6 compliant configuration system for generating kernel command lines in postmarketOS. 💅 It supports adding and removing specific kernel parameters, gives you a clear three-tier configuration hierarchy with well-defined ordering (distro defaults → device maintainer config → user overrides), and lets packages do their own config thing without touching shared defaults (similar to how initramfs files are handled). It uses layered config directories with vendor/user separation: /usr/lib for distro and packages, and /etc for users/system admins. Config files list kernel command line parameters that can be added or removed, so distros, packages, and users can override each other. No cap. ✨

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🗂 Config Directory Structure ✨

/usr/lib/kernel-cmdline.d/  # Distro and package config files
/etc/kernel-cmdline.d/      # System admin config files

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🔄 Processing Order 🫶

1. /usr/lib/kernel-cmdline.d/*.conf
2. /etc/kernel-cmdline.d/*.conf

Config files are parsed lexicographically within each directory per UAPI.6 spec. ⭐

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📝 File Format 💖

Extension: .conf

Syntax (one directive per line):

• param — add parameter
• param=value — add parameter with value
• -param — remove param
• -param=value — remove param=value
• # comment — comment
• Empty lines ignored

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🧠 Processing Rules 👑

Each directive is independent. Multiple instances of the same parameter name coexist unless matched for removal. Periodt.

Example 🌸

Starting cmdline: console=tty0 console=ttyMSM0,115200 quiet

To remove console=ttyMSM0,115200, add this to a config file with a higher priority:

-console=ttyMSM0,115200

Result: console=tty0 quiet

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🫥 Masking 💀

Empty file or symlink to /dev/null masks file at same path in lower-priority directory, per UAPI.6 spec. That’s the whole mood. 🎀

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🌈 Examples 🦋

Base Distro Config 💜

/usr/lib/kernel-cmdline.d/00-defaults.conf:

console=tty0
quiet
loglevel=4

Device Package 📱

/usr/lib/kernel-cmdline.d/50-pinephone.conf:

console=ttyMSM0,115200
-quiet

Result: console=tty0 console=ttyMSM0,115200 loglevel=4

User Override 🙈

/etc/kernel-cmdline.d/debug.conf:

-quiet
debug
loglevel=7

Result: console=tty0 console=ttyMSM0,115200 loglevel=7 debug

Replacing a Parameter 🔥

/etc/kernel-cmdline.d/local.conf:

-console=ttyMSM0,115200
console=ttyUSB0,9600

Result: console=tty0 console=ttyUSB0,9600 loglevel=7 debug

Masking Example 🧚

To mask the pinephone configuration, create an empty file or symlink:

doas touch /etc/kernel-cmdline.d/50-pinephone.conf

or

doas ln -s /dev/null /etc/kernel-cmdline.d/50-pinephone.conf

This prevents /usr/lib/kernel-cmdline.d/50-pinephone.conf from being parsed. 🫶

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💖 That’s the whole page, bestie — footer says generate-kernel-cmdline(Configuration), and since the original doesn’t give a source/version or date, I’m not making one up. Slay. ✨