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 initial RAM disk (initrd) and basic userspace
functionality 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 initial RAM disk, please
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.early_core_pattern=, 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.default_standard_output=, systemd.default_standard_error=,
systemd.setenv=, systemd.machine_id=, systemd.unified_cgroup_hierarchy,
systemd.legacy_systemd_cgroup_controller
Parameters understood by the system and service manager to control
system behavior. For details, see systemd(1).
systemd.mask=, systemd.wants=, systemd.debug_shell
Additional parameters understood by systemd-debug-generator(8), to
mask or start specific units at boot, or invoke a debug shell on
tty9.
systemd.run=, systemd.run_success_action=, systemd.run_failure_action=
Additional parameters understood by systemd-run-generator(8), to
run a command line specified on the kernel command line as system
service after booting up.
systemd.early_core_pattern=
During early boot, the generation of core dump files is disabled
until a core dump handler (if any) takes over. This parameter
allows specifying an absolute path where core dump files should be
stored until a handler is installed. The path should be absolute
and may contain specifiers, see core(5) for details.
systemd.restore_state=
This parameter is understood by several system tools to control
whether or not they should restore system state from the previous
boot. For details, see systemd-backlight@.service(8) and systemd-
rfkill.service(8).
systemd.volatile=
This parameter controls whether the system shall boot up in
volatile mode. Takes a boolean argument, or the special value
"state". If false (the default), normal boot mode is selected, the
root directory and /var are mounted as specified on the kernel
command line or /etc/fstab, or otherwise configured. If true, full
state-less boot mode is selected. In this case the root directory
is mounted as volatile memory file system ("tmpfs"), and only /usr
is mounted from the file system configured as root device, in
read-only mode. This enables fully state-less boots were the
vendor-supplied OS is used as shipped, with only default
configuration and no stored state in effect, as /etc and /var (as
well as all other resources shipped in the root file system) are
reset at boot and lost on shutdown. If this setting is set to
"state" the root file system is mounted read-only, however /var is
mounted as a volatile memory file system ("tmpfs"), so that the
system boots up with the normal configuration applied, but all
state reset at boot and lost at shutdown. If this setting is set to
"overlay" the root file system is set up as "overlayfs" mount
combining the read-only root directory with a writable "tmpfs", so
that no modifications are made to disk, but the file system may be
modified nonetheless with all changes being lost at reboot. For
details, see systemd-volatile-root.service(8) and systemd-fstab-
generator(8).
quiet
Parameter understood by both the kernel and the system and service
manager to control console log verbosity. For details, see
systemd(1).
debug
Parameter understood by both the kernel and the system and service
manager to control console log verbosity. For details, see
systemd(1).
-b, rd.emergency, emergency, rd.rescue, rescue, single, s, S, 1, 2, 3,
4, 5
Parameters understood by the system and service manager, as
compatibility and convenience options. For details, see systemd(1).
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=
Parameters understood by the system and service manager to control
locale and language settings. For details, see systemd(1).
fsck.mode=, fsck.repair=
Parameters understood by the file system checker services. For
details, see systemd-fsck@.service(8).
quotacheck.mode=
Parameter understood by the file quota checker service. For
details, see systemd-quotacheck.service(8).
systemd.journald.forward_to_syslog=, systemd.journald.forward_to_kmsg=,
systemd.journald.forward_to_console=, systemd.journald.forward_to_wall=
Parameters understood by the journal service. For details, see
systemd-journald.service(8).
vconsole.keymap=, vconsole.keymap_toggle=, vconsole.font=,
vconsole.font_map=, vconsole.font_unimap=
Parameters understood by the virtual console setup logic. For
details, see vconsole.conf(5).
udev.log_priority=, rd.udev.log_priority=, udev.children_max=,
rd.udev.children_max=, udev.exec_delay=, rd.udev.exec_delay=,
udev.event_timeout=, rd.udev.event_timeout=, net.ifnames=,
net.naming-scheme=
Parameters understood by the device event managing daemon. For
details, see systemd-udevd.service(8).
plymouth.enable=
May be used to disable the Plymouth boot splash. For details, see
plymouth(8).
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=
Configures the LUKS full-disk encryption logic at boot. For
details, see systemd-cryptsetup-generator(8).
fstab=, rd.fstab=
Configures the /etc/fstab logic at boot. For details, see systemd-
fstab-generator(8).
root=, rootfstype=, rootflags=, ro, rw
Configures the root file system and its file system type and mount
options, as well as whether it shall be mounted read-only or
read-write initially. For details, see systemd-fstab-generator(8).
mount.usr=, mount.usrfstype=, mount.usrflags=
Configures the /usr file system (if required) and its file system
type and mount options. For details, see systemd-fstab-
generator(8).
roothash=, systemd.verity=, rd.systemd.verity=,
systemd.verity_root_data=, systemd.verity_root_hash=
Configures the integrity protection root hash for the root file
system, and other related parameters. For details, see systemd-
veritysetup-generator(8).
systemd.gpt_auto=, rd.systemd.gpt_auto=
Configures whether GPT based partition auto-discovery shall be
attempted. For details, see systemd-gpt-auto-generator(8).
systemd.default_timeout_start_sec=
Overwrites the default start job timeout DefaultTimeoutStartSec= at
boot. For details, see systemd-system.conf(5).
systemd.watchdog_device=
Overwrites the watchdog device path WatchdogDevice=. For details,
see systemd-system.conf(5).
systemd.cpu_affinity=
Overrides the CPU affinity mask for the service manager and the
default for all child processes it forks. This takes precedence
over CPUAffinity=, see systemd-system.conf(5) for details.
modules_load=, rd.modules_load=
Load a specific kernel module early at boot. For details, see
systemd-modules-load.service(8).
resume=, resumeflags=
Enables resume from hibernation using the specified device and
mount options. All fstab(5)-like paths are supported. For details,
see systemd-hibernate-resume-generator(8).
systemd.firstboot=
Takes a boolean argument, defaults to on. If off, systemd-
firstboot.service(8) will not query the user for basic system
settings, even if the system boots up for the first time and the
relevant settings are not initialized yet.
SEE ALSO
systemd(1), systemd-system.conf(5), bootparam(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-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
https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
systemd 245 KERNEL-COMMAND-LINE(7)