1KERNEL-COMMAND-LINE(7)        kernel-command-line       KERNEL-COMMAND-LINE(7)
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NAME

6       kernel-command-line - Kernel command line parameters
7

SYNOPSIS

9       /proc/cmdline
10

DESCRIPTION

12       The kernel, the initial RAM disk (initrd) and basic userspace
13       functionality may be configured at boot via kernel command line
14       arguments. In addition, various systemd tools look at the EFI variable
15       "SystemdOptions" (if available). Both sources are combined, but the
16       kernel command line has higher priority. Please note that the EFI
17       variable is only used by systemd tools, and is ignored by the kernel
18       and other user space tools, so it is not a replacement for the kernel
19       command line.
20
21       For command line parameters understood by the kernel, please see
22       kernel-parameters.html[1] and bootparam(7).
23
24       For command line parameters understood by the initial RAM disk, please
25       see dracut.cmdline(7), or the documentation of the specific initrd
26       implementation of your installation.
27

CORE OS COMMAND LINE ARGUMENTS

29       systemd.unit=, rd.systemd.unit=, systemd.dump_core,
30       systemd.early_core_pattern=, systemd.crash_chvt, systemd.crash_shell,
31       systemd.crash_reboot, systemd.confirm_spawn, systemd.service_watchdogs,
32       systemd.show_status, systemd.status_unit_format=, systemd.log_target=,
33       systemd.log_level=, systemd.log_location=, systemd.log_color,
34       systemd.default_standard_output=, systemd.default_standard_error=,
35       systemd.setenv=, systemd.machine_id=, systemd.unified_cgroup_hierarchy,
36       systemd.legacy_systemd_cgroup_controller
37           Parameters understood by the system and service manager to control
38           system behavior. For details, see systemd(1).
39
40       systemd.mask=, systemd.wants=, systemd.debug_shell
41           Additional parameters understood by systemd-debug-generator(8), to
42           mask or start specific units at boot, or invoke a debug shell on
43           tty9.
44
45       systemd.run=, systemd.run_success_action=, systemd.run_failure_action=
46           Additional parameters understood by systemd-run-generator(8), to
47           run a command line specified on the kernel command line as system
48           service after booting up.
49
50       systemd.early_core_pattern=
51           During early boot, the generation of core dump files is disabled
52           until a core dump handler (if any) takes over. This parameter
53           allows specifying an absolute path where core dump files should be
54           stored until a handler is installed. The path should be absolute
55           and may contain specifiers, see core(5) for details.
56
57       systemd.restore_state=
58           This parameter is understood by several system tools to control
59           whether or not they should restore system state from the previous
60           boot. For details, see systemd-backlight@.service(8) and systemd-
61           rfkill.service(8).
62
63       systemd.volatile=
64           This parameter controls whether the system shall boot up in
65           volatile mode. Takes a boolean argument, or the special value
66           "state". If false (the default), normal boot mode is selected, the
67           root directory and /var are mounted as specified on the kernel
68           command line or /etc/fstab, or otherwise configured. If true, full
69           state-less boot mode is selected. In this case the root directory
70           is mounted as volatile memory file system ("tmpfs"), and only /usr
71           is mounted from the file system configured as root device, in
72           read-only mode. This enables fully state-less boots were the
73           vendor-supplied OS is used as shipped, with only default
74           configuration and no stored state in effect, as /etc and /var (as
75           well as all other resources shipped in the root file system) are
76           reset at boot and lost on shutdown. If this setting is set to
77           "state" the root file system is mounted read-only, however /var is
78           mounted as a volatile memory file system ("tmpfs"), so that the
79           system boots up with the normal configuration applied, but all
80           state reset at boot and lost at shutdown. If this setting is set to
81           "overlay" the root file system is set up as "overlayfs" mount
82           combining the read-only root directory with a writable "tmpfs", so
83           that no modifications are made to disk, but the file system may be
84           modified nonetheless with all changes being lost at reboot. For
85           details, see systemd-volatile-root.service(8) and systemd-fstab-
86           generator(8).
87
88       quiet
89           Parameter understood by both the kernel and the system and service
90           manager to control console log verbosity. For details, see
91           systemd(1).
92
93       debug
94           Parameter understood by both the kernel and the system and service
95           manager to control console log verbosity. For details, see
96           systemd(1).
97
98       -b, rd.emergency, emergency, rd.rescue, rescue, single, s, S, 1, 2, 3,
99       4, 5
100           Parameters understood by the system and service manager, as
101           compatibility and convenience options. For details, see systemd(1).
102
103       locale.LANG=, locale.LANGUAGE=, locale.LC_CTYPE=, locale.LC_NUMERIC=,
104       locale.LC_TIME=, locale.LC_COLLATE=, locale.LC_MONETARY=,
105       locale.LC_MESSAGES=, locale.LC_PAPER=, locale.LC_NAME=,
106       locale.LC_ADDRESS=, locale.LC_TELEPHONE=, locale.LC_MEASUREMENT=,
107       locale.LC_IDENTIFICATION=
108           Parameters understood by the system and service manager to control
109           locale and language settings. For details, see systemd(1).
110
111       fsck.mode=, fsck.repair=
112           Parameters understood by the file system checker services. For
113           details, see systemd-fsck@.service(8).
114
115       quotacheck.mode=
116           Parameter understood by the file quota checker service. For
117           details, see systemd-quotacheck.service(8).
118
119       systemd.journald.forward_to_syslog=, systemd.journald.forward_to_kmsg=,
120       systemd.journald.forward_to_console=, systemd.journald.forward_to_wall=
121           Parameters understood by the journal service. For details, see
122           systemd-journald.service(8).
123
124       vconsole.keymap=, vconsole.keymap_toggle=, vconsole.font=,
125       vconsole.font_map=, vconsole.font_unimap=
126           Parameters understood by the virtual console setup logic. For
127           details, see vconsole.conf(5).
128
129       udev.log_priority=, rd.udev.log_priority=, udev.children_max=,
130       rd.udev.children_max=, udev.exec_delay=, rd.udev.exec_delay=,
131       udev.event_timeout=, rd.udev.event_timeout=, net.ifnames=,
132       net.naming-scheme=
133           Parameters understood by the device event managing daemon. For
134           details, see systemd-udevd.service(8).
135
136       plymouth.enable=
137           May be used to disable the Plymouth boot splash. For details, see
138           plymouth(8).
139
140       luks=, rd.luks=, luks.crypttab=, rd.luks.crypttab=, luks.name=,
141       rd.luks.name=, luks.uuid=, rd.luks.uuid=, luks.options=,
142       rd.luks.options=, luks.key=, rd.luks.key=
143           Configures the LUKS full-disk encryption logic at boot. For
144           details, see systemd-cryptsetup-generator(8).
145
146       fstab=, rd.fstab=
147           Configures the /etc/fstab logic at boot. For details, see systemd-
148           fstab-generator(8).
149
150       root=, rootfstype=, rootflags=, ro, rw
151           Configures the root file system and its file system type and mount
152           options, as well as whether it shall be mounted read-only or
153           read-write initially. For details, see systemd-fstab-generator(8).
154
155       mount.usr=, mount.usrfstype=, mount.usrflags=
156           Configures the /usr file system (if required) and its file system
157           type and mount options. For details, see systemd-fstab-
158           generator(8).
159
160       roothash=, systemd.verity=, rd.systemd.verity=,
161       systemd.verity_root_data=, systemd.verity_root_hash=
162           Configures the integrity protection root hash for the root file
163           system, and other related parameters. For details, see systemd-
164           veritysetup-generator(8).
165
166       systemd.gpt_auto=, rd.systemd.gpt_auto=
167           Configures whether GPT based partition auto-discovery shall be
168           attempted. For details, see systemd-gpt-auto-generator(8).
169
170       systemd.default_timeout_start_sec=
171           Overwrites the default start job timeout DefaultTimeoutStartSec= at
172           boot. For details, see systemd-system.conf(5).
173
174       systemd.watchdog_device=
175           Overwrites the watchdog device path WatchdogDevice=. For details,
176           see systemd-system.conf(5).
177
178       systemd.cpu_affinity=
179           Overrides the CPU affinity mask for the service manager and the
180           default for all child processes it forks. This takes precedence
181           over CPUAffinity=, see systemd-system.conf(5) for details.
182
183       modules_load=, rd.modules_load=
184           Load a specific kernel module early at boot. For details, see
185           systemd-modules-load.service(8).
186
187       resume=, resumeflags=
188           Enables resume from hibernation using the specified device and
189           mount options. All fstab(5)-like paths are supported. For details,
190           see systemd-hibernate-resume-generator(8).
191
192       systemd.firstboot=
193           Takes a boolean argument, defaults to on. If off, systemd-
194           firstboot.service(8) will not query the user for basic system
195           settings, even if the system boots up for the first time and the
196           relevant settings are not initialized yet.
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SEE ALSO

199       systemd(1), systemd-system.conf(5), bootparam(7), dracut.cmdline(7),
200       systemd-debug-generator(8), systemd-fsck@.service(8), systemd-
201       quotacheck.service(8), systemd-journald.service(8), systemd-vconsole-
202       setup.service(8), systemd-udevd.service(8), plymouth(8), systemd-
203       cryptsetup-generator(8), systemd-veritysetup-generator(8), systemd-
204       fstab-generator(8), systemd-gpt-auto-generator(8), systemd-volatile-
205       root.service(8), systemd-modules-load.service(8), systemd-
206       backlight@.service(8), systemd-rfkill.service(8), systemd-hibernate-
207       resume-generator(8), systemd-firstboot.service(8), bootctl(1)
208

NOTES

210        1. kernel-parameters.html
211           https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
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215systemd 245                                             KERNEL-COMMAND-LINE(7)
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