1KERNEL-COMMAND-LINE(7) kernel-command-line KERNEL-COMMAND-LINE(7)
2
6 kernel-command-line - Kernel command line parameters
7
9 /proc/cmdline
10
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 For command line parameters understood by the kernel, please see
22 kernel-parameters.html[1] and bootparam(7).
23 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
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 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 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 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 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 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 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 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 -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 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 fsck.mode=, fsck.repair=
112 Parameters understood by the file system checker services. For
113 details, see systemd-fsck@.service(8).
114 quotacheck.mode=
116 Parameter understood by the file quota checker service. For
117 details, see systemd-quotacheck.service(8).
118 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 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 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 plymouth.enable=
137 May be used to disable the Plymouth boot splash. For details, see
138 plymouth(8).
139 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 fstab=, rd.fstab=
147 Configures the /etc/fstab logic at boot. For details, see systemd-
148 fstab-generator(8).
149 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 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 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 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 systemd.default_timeout_start_sec=
171 Overwrites the default start job timeout DefaultTimeoutStartSec= at
172 boot. For details, see systemd-system.conf(5).
173 systemd.watchdog_device=
175 Overwrites the watchdog device path WatchdogDevice=. For details,
176 see systemd-system.conf(5).
177 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 modules_load=, rd.modules_load=
184 Load a specific kernel module early at boot. For details, see
185 systemd-modules-load.service(8).
186 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 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.
197
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
210 1. kernel-parameters.html
211 https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html
212systemd 245 KERNEL-COMMAND-LINE(7)