finit/doc/cmdline.md

Tips & Tricks with the kernel cmdline

This document summarizes the different boot parameters that can be passed on the Linux kernel command line. Not limited to Finit.

The bool setting is one of on, off, true false, 1, 0.

NOTE: remember to use -- to separate kernel parameters from parameters to init. E.g., init=/sbin/finit -- finit.debug rescue

• debug: Enable kernel debug. Debug messages are printed to the console until Finit starts up, unless loglevel=7 (below) is used.

• finit.debug[=bool]: Enable finit debug. This is operated independently of the kernel debug setting. New as of Finit v4.

• finit.status[=bool]: Control finit boot progress, including banner. (Used to be finit.show_status, which works but is deprecated.)

• finit.status_style=<classic,modern>: Set Finit boot progress style, when enabled.

• init=/bin/sh: Bypass system default init and tell kernel to start a shell. Note, this shell is very limited and does not support signals and has no job control. Recommend using, and modifying, rescue mode instead.

• loglevel=<0-7>, sets the kernel's log level, which is more granular than debug. Also, when loglevel=7, Finit will not disable kernel logs to the console. This is very useful when debugging the kernel at system bring-up. Since loglevel=7 is the same as debug this means you have to use quiet for a quiet boot, until sysklogd takes over logging of kernel events.

• panic=SEC: By default the kernel does not reboot after a kernel panic. This setting will cause a kernel reboot after SEC seconds.

• quiet: Suppress kernel logging to console, except for warnings and errors. Also, see loglevel and quiet above.

• rescue: Start rescue/maintenance mode. If your system comes with the bundled sulogin program (Finit, or from util-linux/Busybox), you will be given a root login to a maintenance shell. However, if sulogin is missing, the file /lib/finit/rescue.conf is read and the system booted in a limited fallback mode. See config.md for more information.

• single, or S: Single user mode, runlevel 1, in Finit. Useful to debug problems with the regular runlevel. All services and TTYs in [1] will be started, so a tty [1] @console nologin configuration presents you with a root console without login.

For more on kernel boot parameters, see the man page bootparam(7).