table of contents
- bookworm 252.30-1~deb12u2
- bookworm-backports 254.16-1~bpo12+1
- testing 256.6-1
- unstable 256.6-1
KERNEL-COMMAND-LINE(7) | kernel-command-line | KERNEL-COMMAND-LINE(7) |
NAME¶
kernel-command-line - Kernel command line parameters
SYNOPSIS¶
/proc/cmdline
DESCRIPTION¶
The kernel, the programs running in the initrd and in the host system may be configured at boot via kernel command line arguments. In addition, various systemd tools look at the EFI variable "SystemdOptions" (if available). Both sources are combined, but the kernel command line has higher priority. Please note that the EFI variable is only used by systemd tools, and is ignored by the kernel and other user space tools, so it is not a replacement for the kernel command line.
For command line parameters understood by the kernel, please see kernel-parameters.html[1] and bootparam(7).
For command line parameters understood by the initrd, see dracut.cmdline(7), or the documentation of the specific initrd implementation of your installation.
CORE OS COMMAND LINE ARGUMENTS¶
systemd.unit=, rd.systemd.unit=, systemd.dump_core, systemd.crash_chvt, systemd.crash_shell, systemd.crash_reboot, systemd.confirm_spawn, systemd.service_watchdogs, systemd.show_status, systemd.status_unit_format=, systemd.log_target=, systemd.log_level=, systemd.log_location=, systemd.log_color, systemd.log_ratelimit_kmsg, systemd.default_standard_output=, systemd.default_standard_error=, systemd.setenv=, systemd.machine_id=, systemd.set_credential=, systemd.set_credential_binary=, systemd.import_credentials=, systemd.reload_limit_interval_sec=, systemd.reload_limit_burst=
systemd.mask=, systemd.wants=, systemd.debug_shell
systemd.run=, systemd.run_success_action=, systemd.run_failure_action=
systemd.early_core_pattern=
systemd.restore_state=
systemd.volatile=
quiet
debug
-b, rd.emergency, emergency, rd.rescue, rescue, single, s, S, 1, 2, 3, 4, 5
locale.LANG=, locale.LANGUAGE=, locale.LC_CTYPE=, locale.LC_NUMERIC=, locale.LC_TIME=, locale.LC_COLLATE=, locale.LC_MONETARY=, locale.LC_MESSAGES=, locale.LC_PAPER=, locale.LC_NAME=, locale.LC_ADDRESS=, locale.LC_TELEPHONE=, locale.LC_MEASUREMENT=, locale.LC_IDENTIFICATION=
fsck.mode=, fsck.repair=
quotacheck.mode=
systemd.journald.forward_to_syslog=, systemd.journald.forward_to_kmsg=, systemd.journald.forward_to_console=, systemd.journald.forward_to_wall=
vconsole.keymap=, vconsole.keymap_toggle=, vconsole.font=, vconsole.font_map=, vconsole.font_unimap=
udev.log_level=, rd.udev.log_level=, udev.children_max=, rd.udev.children_max=, udev.exec_delay=, rd.udev.exec_delay=, udev.event_timeout=, rd.udev.event_timeout=, udev.timeout_signal=, rd.udev.timeout_signal=, udev.blockdev_read_only, rd.udev.blockdev_read_only, net.ifnames=, net.naming-scheme=
plymouth.enable=
luks=, rd.luks=, luks.crypttab=, rd.luks.crypttab=, luks.name=, rd.luks.name=, luks.uuid=, rd.luks.uuid=, luks.options=, rd.luks.options=, luks.key=, rd.luks.key=
fstab=, rd.fstab=
root=, rootfstype=, rootflags=, ro, rw
If root= is not set (or set to "gpt-auto") the automatic root partition discovery implemented by systemd-gpt-auto-generator(8) will be in effect. In this case rootfstype=, rootflags=, ro, rw will be interpreted by systemd-gpt-auto-generator.
mount.usr=, mount.usrfstype=, mount.usrflags=
veritytab=, rd.veritytab=, roothash=, systemd.verity=, rd.systemd.verity=, systemd.verity_root_data=, systemd.verity_root_hash=, systemd.verity.root_options=, usrhash=, systemd.verity_usr_data=, systemd.verity_usr_hash=, systemd.verity_usr_options=
systemd.getty_auto=
systemd.gpt_auto=, rd.systemd.gpt_auto=
systemd.image_policy=, rd.systemd.image_policy=
systemd.default_timeout_start_sec=
systemd.default_device_timeout_sec=
systemd.watchdog_device=
systemd.watchdog_sec=
systemd.watchdog_pre_sec=
systemd.watchdog_pretimeout_governor=
systemd.cpu_affinity=
modules_load=, rd.modules_load=
nameserver=, domain=
resume=, resumeflags=
systemd.firstboot=
systemd.condition-needs-update=
systemd.condition-first-boot=
systemd.clock-usec=
systemd.random-seed=
Note that if this option is used the seed is accessible to unprivileged programs from /proc/cmdline. This option is hence a security risk when used outside of test systems, since the (possibly) only seed used for initialization of the kernel's entropy pool might be easily acquired by unprivileged programs.
It is recommended to pass 512 bytes of randomized data (as that matches the Linux kernel pool size), which may be generated with a command like the following:
dd if=/dev/urandom bs=512 count=1 status=none | base64 -w 0
Again: do not use this option outside of testing environments, it's a security risk elsewhere, as secret key material derived from the entropy pool can possibly be reconstructed by unprivileged programs.
systemd.hostname=
systemd.tty.term.tty=, systemd.tty.rows.tty=, systemd.tty.columns.tty=
systemd.battery_check=
ifname=, net.ifname_policy=
HISTORY¶
systemd 252
SEE ALSO¶
systemd(1), systemd-system.conf(5), bootparam(7), systemd.system-credentials(7) smbios-type-11(7), dracut.cmdline(7), systemd-debug-generator(8), systemd-fsck@.service(8), systemd-quotacheck.service(8), systemd-journald.service(8), systemd-vconsole-setup.service(8), systemd-udevd.service(8), plymouth(8), systemd-cryptsetup-generator(8), systemd-veritysetup-generator(8), systemd-fstab-generator(8), systemd-getty-generator(8), systemd-gpt-auto-generator(8), systemd-volatile-root.service(8), systemd-modules-load.service(8), systemd-backlight@.service(8), systemd-rfkill.service(8), systemd-hibernate-resume-generator(8), systemd-firstboot.service(8), bootctl(1)
NOTES¶
- 1.
- kernel-parameters.html
systemd 254 |