]> git.ipfire.org Git - thirdparty/systemd.git/blame - man/kernel-command-line.xml
man: fix link markup
[thirdparty/systemd.git] / man / kernel-command-line.xml
CommitLineData
c66e7bc7 1<?xml version='1.0'?> <!--*-nxml-*-->
3a54a157 2<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
12b42c76 3 "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
0307f791 4<!-- SPDX-License-Identifier: LGPL-2.1+ -->
c66e7bc7
LP
5
6<refentry id="kernel-command-line">
7
798d3a52
ZJS
8 <refentryinfo>
9 <title>kernel-command-line</title>
10 <productname>systemd</productname>
798d3a52
ZJS
11 </refentryinfo>
12
13 <refmeta>
14 <refentrytitle>kernel-command-line</refentrytitle>
15 <manvolnum>7</manvolnum>
16 </refmeta>
17
18 <refnamediv>
19 <refname>kernel-command-line</refname>
20 <refpurpose>Kernel command line parameters</refpurpose>
21 </refnamediv>
22
23 <refsynopsisdiv>
24 <para><filename>/proc/cmdline</filename></para>
25 </refsynopsisdiv>
26
27 <refsect1>
28 <title>Description</title>
29
28f0aef4
ZJS
30 <para>The kernel, the initial RAM disk (initrd) and basic userspace functionality may be configured at
31 boot via kernel command line arguments. In addition, various systemd tools look at the EFI variable
32 <literal>SystemdOptions</literal> (if available). Both sources are combined, but the kernel command line
33 has higher priority. Please note that <emphasis>the EFI variable is only used by systemd tools, and is
34 ignored by the kernel and other user space tools</emphasis>, so it is not a replacement for the kernel
35 command line.</para>
798d3a52
ZJS
36
37 <para>For command line parameters understood by the kernel, please
ab1f7245
ZJS
38 see
39 <ulink url="https://www.kernel.org/doc/html/latest/admin-guide/kernel-parameters.html"><filename>kernel-parameters.html</filename></ulink>
798d3a52
ZJS
40 and
41 <citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
42
43 <para>For command line parameters understood by the initial RAM
44 disk, please see
af105d03 45 <citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
798d3a52
ZJS
46 or the documentation of the specific initrd implementation of your
47 installation.</para>
48 </refsect1>
49
50 <refsect1>
51 <title>Core OS Command Line Arguments</title>
52
53 <variablelist class='kernel-commandline-options'>
54 <varlistentry>
55 <term><varname>systemd.unit=</varname></term>
56 <term><varname>rd.systemd.unit=</varname></term>
770c4777 57 <term><varname>systemd.dump_core</varname></term>
c6885f5f 58 <term><varname>systemd.early_core_pattern=</varname></term>
770c4777
ZJS
59 <term><varname>systemd.crash_chvt</varname></term>
60 <term><varname>systemd.crash_shell</varname></term>
61 <term><varname>systemd.crash_reboot</varname></term>
62 <term><varname>systemd.confirm_spawn</varname></term>
2a12e32e 63 <term><varname>systemd.service_watchdogs</varname></term>
770c4777 64 <term><varname>systemd.show_status</varname></term>
36cf4507 65 <term><varname>systemd.status_unit_format=</varname></term>
798d3a52
ZJS
66 <term><varname>systemd.log_target=</varname></term>
67 <term><varname>systemd.log_level=</varname></term>
798d3a52 68 <term><varname>systemd.log_location=</varname></term>
770c4777 69 <term><varname>systemd.log_color</varname></term>
798d3a52
ZJS
70 <term><varname>systemd.default_standard_output=</varname></term>
71 <term><varname>systemd.default_standard_error=</varname></term>
72 <term><varname>systemd.setenv=</varname></term>
ee48dbd5 73 <term><varname>systemd.machine_id=</varname></term>
ee075513
ZJS
74 <term><varname>systemd.unified_cgroup_hierarchy</varname></term>
75 <term><varname>systemd.legacy_systemd_cgroup_controller</varname></term>
798d3a52
ZJS
76 <listitem>
77 <para>Parameters understood by the system and service
78 manager to control system behavior. For details, see
79 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
80 </listitem>
81 </varlistentry>
82
83 <varlistentry>
84 <term><varname>systemd.mask=</varname></term>
85 <term><varname>systemd.wants=</varname></term>
1d84ad94 86 <term><varname>systemd.debug_shell</varname></term>
798d3a52
ZJS
87 <listitem>
88 <para>Additional parameters understood by
89 <citerefentry><refentrytitle>systemd-debug-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
90 to mask or start specific units at boot, or invoke a debug
91 shell on tty9.</para>
92 </listitem>
93 </varlistentry>
94
565f3d91
LP
95 <varlistentry>
96 <term><varname>systemd.run=</varname></term>
97 <term><varname>systemd.run_success_action=</varname></term>
98 <term><varname>systemd.run_failure_action=</varname></term>
99 <listitem>
100 <para>Additional parameters understood by
101 <citerefentry><refentrytitle>systemd-run-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>, to
102 run a command line specified on the kernel command line as system service after booting up.</para>
103 </listitem>
104 </varlistentry>
105
c6885f5f
FB
106 <varlistentry>
107 <term><varname>systemd.early_core_pattern=</varname></term>
108 <listitem>
109 <para>During early boot, the generation of core dump files is disabled until a core dump handler (if any)
11fcfc53 110 takes over. This parameter allows specifying an absolute path where core dump files should be stored until
c6885f5f 111 a handler is installed. The path should be absolute and may contain specifiers, see
b7a47345 112 <citerefentry project='man-pages'><refentrytitle>core</refentrytitle><manvolnum>5</manvolnum></citerefentry> for details.</para>
c6885f5f
FB
113 </listitem>
114 </varlistentry>
115
798d3a52
ZJS
116 <varlistentry>
117 <term><varname>systemd.restore_state=</varname></term>
118 <listitem>
119 <para>This parameter is understood by several system tools
120 to control whether or not they should restore system state
121 from the previous boot. For details, see
122 <citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
123 and
af105d03 124 <citerefentry><refentrytitle>systemd-rfkill.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.
798d3a52
ZJS
125 </para>
126 </listitem>
127 </varlistentry>
128
91214a37
LP
129 <varlistentry>
130 <term><varname>systemd.volatile=</varname></term>
131 <listitem>
132 <para>This parameter controls whether the system shall boot up in volatile mode. Takes a boolean argument, or
133 the special value <literal>state</literal>. If false (the default), normal boot mode is selected, the root
134 directory and <filename>/var</filename> are mounted as specified on the kernel command line or
135 <filename>/etc/fstab</filename>, or otherwise configured. If true, full state-less boot mode is selected. In
136 this case the root directory is mounted as volatile memory file system (<literal>tmpfs</literal>), and only
137 <filename>/usr</filename> is mounted from the file system configured as root device, in read-only mode. This
138 enables fully state-less boots were the vendor-supplied OS is used as shipped, with only default
139 configuration and no stored state in effect, as <filename>/etc</filename> and <filename>/var</filename> (as
140 well as all other resources shipped in the root file system) are reset at boot and lost on shutdown. If this
13070a70 141 setting is set to <literal>state</literal> the root file system is mounted read-only, however
91214a37 142 <filename>/var</filename> is mounted as a volatile memory file system (<literal>tmpfs</literal>), so that the
13070a70
LP
143 system boots up with the normal configuration applied, but all state reset at boot and lost at shutdown. If
144 this setting is set to <literal>overlay</literal> the root file system is set up as
145 <literal>overlayfs</literal> mount combining the read-only root directory with a writable
146 <literal>tmpfs</literal>, so that no modifications are made to disk, but the file system may be modified
147 nonetheless with all changes being lost at reboot. For details, see
91214a37
LP
148 <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
149 and
150 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
151 </listitem>
152 </varlistentry>
153
798d3a52
ZJS
154 <varlistentry>
155 <term><varname>quiet</varname></term>
156 <listitem>
157 <para>Parameter understood by both the kernel and the system
158 and service manager to control console log verbosity. For
159 details, see
160 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
161 </listitem>
162 </varlistentry>
163
164 <varlistentry>
165 <term><varname>debug</varname></term>
166 <listitem>
167 <para>Parameter understood by both the kernel and the system
168 and service manager to control console log verbosity. For
169 details, see
170 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
171 </listitem>
172 </varlistentry>
173
174 <varlistentry>
175 <term><varname>-b</varname></term>
dcd61450 176 <term><varname>rd.emergency</varname></term>
798d3a52 177 <term><varname>emergency</varname></term>
dcd61450 178 <term><varname>rd.rescue</varname></term>
798d3a52
ZJS
179 <term><varname>rescue</varname></term>
180 <term><varname>single</varname></term>
181 <term><varname>s</varname></term>
182 <term><varname>S</varname></term>
183 <term><varname>1</varname></term>
184 <term><varname>2</varname></term>
185 <term><varname>3</varname></term>
186 <term><varname>4</varname></term>
187 <term><varname>5</varname></term>
188 <listitem>
189 <para>Parameters understood by the system and service
dcd61450 190 manager, as compatibility and convenience options. For details, see
798d3a52
ZJS
191 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
192 </listitem>
193 </varlistentry>
194
195 <varlistentry>
196 <term><varname>locale.LANG=</varname></term>
197 <term><varname>locale.LANGUAGE=</varname></term>
198 <term><varname>locale.LC_CTYPE=</varname></term>
199 <term><varname>locale.LC_NUMERIC=</varname></term>
200 <term><varname>locale.LC_TIME=</varname></term>
201 <term><varname>locale.LC_COLLATE=</varname></term>
202 <term><varname>locale.LC_MONETARY=</varname></term>
203 <term><varname>locale.LC_MESSAGES=</varname></term>
204 <term><varname>locale.LC_PAPER=</varname></term>
205 <term><varname>locale.LC_NAME=</varname></term>
206 <term><varname>locale.LC_ADDRESS=</varname></term>
207 <term><varname>locale.LC_TELEPHONE=</varname></term>
208 <term><varname>locale.LC_MEASUREMENT=</varname></term>
209 <term><varname>locale.LC_IDENTIFICATION=</varname></term>
210 <listitem>
211 <para>Parameters understood by the system and service
212 manager to control locale and language settings. For
213 details, see
214 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>.</para>
215 </listitem>
216 </varlistentry>
217
218 <varlistentry>
219 <term><varname>fsck.mode=</varname></term>
220 <term><varname>fsck.repair=</varname></term>
221
222 <listitem>
223 <para>Parameters understood by the file system checker
224 services. For details, see
225 <citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
226 </listitem>
227 </varlistentry>
228
229 <varlistentry>
230 <term><varname>quotacheck.mode=</varname></term>
231
232 <listitem>
233 <para>Parameter understood by the file quota checker
234 service. For details, see
235 <citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
236 </listitem>
237 </varlistentry>
238
239 <varlistentry>
240 <term><varname>systemd.journald.forward_to_syslog=</varname></term>
241 <term><varname>systemd.journald.forward_to_kmsg=</varname></term>
242 <term><varname>systemd.journald.forward_to_console=</varname></term>
243 <term><varname>systemd.journald.forward_to_wall=</varname></term>
244
245 <listitem>
246 <para>Parameters understood by the journal service. For
247 details, see
248 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
249 </listitem>
250 </varlistentry>
251
252 <varlistentry>
253 <term><varname>vconsole.keymap=</varname></term>
72ccee50 254 <term><varname>vconsole.keymap_toggle=</varname></term>
798d3a52 255 <term><varname>vconsole.font=</varname></term>
72ccee50
ZJS
256 <term><varname>vconsole.font_map=</varname></term>
257 <term><varname>vconsole.font_unimap=</varname></term>
798d3a52
ZJS
258
259 <listitem>
72ccee50
ZJS
260 <para>Parameters understood by the virtual console setup logic. For details, see
261 <citerefentry><refentrytitle>vconsole.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
798d3a52
ZJS
262 </listitem>
263 </varlistentry>
264
265 <varlistentry>
1d84ad94
LP
266 <term><varname>udev.log_priority=</varname></term>
267 <term><varname>rd.udev.log_priority=</varname></term>
268 <term><varname>udev.children_max=</varname></term>
269 <term><varname>rd.udev.children_max=</varname></term>
270 <term><varname>udev.exec_delay=</varname></term>
271 <term><varname>rd.udev.exec_delay=</varname></term>
272 <term><varname>udev.event_timeout=</varname></term>
273 <term><varname>rd.udev.event_timeout=</varname></term>
e2099267
MS
274 <term><varname>udev.timeout_signal=</varname></term>
275 <term><varname>rd.udev.timeout_signal=</varname></term>
95ac5230
LP
276 <term><varname>udev.blockdev_read_only</varname></term>
277 <term><varname>rd.udev.blockdev_read_only</varname></term>
798d3a52 278 <term><varname>net.ifnames=</varname></term>
f7e81fd9 279 <term><varname>net.naming-scheme=</varname></term>
798d3a52
ZJS
280
281 <listitem>
282 <para>Parameters understood by the device event managing
283 daemon. For details, see
284 <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
285 </listitem>
286 </varlistentry>
287
288 <varlistentry>
289 <term><varname>plymouth.enable=</varname></term>
290
291 <listitem>
292 <para>May be used to disable the Plymouth boot splash. For
293 details, see
294 <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
295 </listitem>
296 </varlistentry>
297
298 <varlistentry>
299 <term><varname>luks=</varname></term>
300 <term><varname>rd.luks=</varname></term>
301 <term><varname>luks.crypttab=</varname></term>
302 <term><varname>rd.luks.crypttab=</varname></term>
303 <term><varname>luks.name=</varname></term>
304 <term><varname>rd.luks.name=</varname></term>
305 <term><varname>luks.uuid=</varname></term>
306 <term><varname>rd.luks.uuid=</varname></term>
307 <term><varname>luks.options=</varname></term>
308 <term><varname>rd.luks.options=</varname></term>
309 <term><varname>luks.key=</varname></term>
310 <term><varname>rd.luks.key=</varname></term>
311
312 <listitem>
313 <para>Configures the LUKS full-disk encryption logic at
314 boot. For details, see
315 <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
316 </listitem>
317 </varlistentry>
318
319 <varlistentry>
320 <term><varname>fstab=</varname></term>
321 <term><varname>rd.fstab=</varname></term>
322
323 <listitem>
324 <para>Configures the <filename>/etc/fstab</filename> logic
325 at boot. For details, see
326 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
327 </listitem>
328 </varlistentry>
329
330 <varlistentry>
331 <term><varname>root=</varname></term>
332 <term><varname>rootfstype=</varname></term>
d6a12e7c 333 <term><varname>rootflags=</varname></term>
798d3a52
ZJS
334 <term><varname>ro</varname></term>
335 <term><varname>rw</varname></term>
336
337 <listitem>
338 <para>Configures the root file system and its file system
339 type and mount options, as well as whether it shall be
17ec531f 340 mounted read-only or read-write initially. For details,
798d3a52
ZJS
341 see
342 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
343 </listitem>
344 </varlistentry>
345
6dfcea32
TH
346 <varlistentry>
347 <term><varname>mount.usr=</varname></term>
348 <term><varname>mount.usrfstype=</varname></term>
349 <term><varname>mount.usrflags=</varname></term>
350
351 <listitem>
352 <para>Configures the /usr file system (if required) and
353 its file system type and mount options. For details, see
354 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
355 </listitem>
356 </varlistentry>
357
2f3dfc6f
LP
358 <varlistentry>
359 <term><varname>roothash=</varname></term>
360 <term><varname>systemd.verity=</varname></term>
361 <term><varname>rd.systemd.verity=</varname></term>
362 <term><varname>systemd.verity_root_data=</varname></term>
363 <term><varname>systemd.verity_root_hash=</varname></term>
364 <listitem>
365 <para>Configures the integrity protection root hash for the root file system, and other related
366 parameters. For details, see
367 <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
368 </listitem>
369 </varlistentry>
370
798d3a52
ZJS
371 <varlistentry>
372 <term><varname>systemd.gpt_auto=</varname></term>
373 <term><varname>rd.systemd.gpt_auto=</varname></term>
374
375 <listitem>
376 <para>Configures whether GPT based partition auto-discovery
377 shall be attempted. For details, see
378 <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
379 </listitem>
380 </varlistentry>
381
959718c6
TB
382 <varlistentry>
383 <term><varname>systemd.default_timeout_start_sec=</varname></term>
384
385 <listitem>
386 <para>Overwrites the default start job timeout <varname>DefaultTimeoutStartSec=</varname> at boot. For details,
387 see <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
c75396c3
EJ
388 </listitem>
389 </varlistentry>
390
391 <varlistentry>
392 <term><varname>systemd.watchdog_device=</varname></term>
393
394 <listitem>
395 <para>Overwrites the watchdog device path <varname>WatchdogDevice=</varname>. For details, see
396 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>.</para>
959718c6
TB
397 </listitem>
398 </varlistentry>
399
68d58f38
LP
400 <varlistentry>
401 <term><varname>systemd.cpu_affinity=</varname></term>
402
403 <listitem>
404 <para>Overrides the CPU affinity mask for the service manager and the default for all child
405 processes it forks. This takes precedence over <varname>CPUAffinity=</varname>, see
406 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>
407 for details.</para>
408 </listitem>
409 </varlistentry>
410
798d3a52 411 <varlistentry>
1d84ad94
LP
412 <term><varname>modules_load=</varname></term>
413 <term><varname>rd.modules_load=</varname></term>
798d3a52
ZJS
414
415 <listitem>
416 <para>Load a specific kernel module early at boot. For
417 details, see
418 <citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
419 </listitem>
420 </varlistentry>
421
422 <varlistentry>
423 <term><varname>resume=</varname></term>
8b6805a2 424 <term><varname>resumeflags=</varname></term>
798d3a52
ZJS
425
426 <listitem>
427 <para>Enables resume from hibernation using the specified
8b6805a2 428 device and mount options. All
3ba3a79d 429 <citerefentry project='man-pages'><refentrytitle>fstab</refentrytitle><manvolnum>5</manvolnum></citerefentry>-like
798d3a52
ZJS
430 paths are supported. For details, see
431 <citerefentry><refentrytitle>systemd-hibernate-resume-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>.</para>
432 </listitem>
433 </varlistentry>
f582cbca
LP
434
435 <varlistentry>
436 <term><varname>systemd.firstboot=</varname></term>
437
438 <listitem><para>Takes a boolean argument, defaults to on. If off,
439 <citerefentry><refentrytitle>systemd-firstboot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>
814872e9
LP
440 will not query the user for basic system settings, even if the system boots up for the first time and
441 the relevant settings are not initialized yet. Not to be confused with
442 <varname>systemd.condition-first-boot=</varname> (see below), which overrides the result of the
443 <varname>ConditionFirstBoot=</varname> unit file condition, and thus controls more than just
444 <filename>systemd-firstboot.service</filename> behaviour.</para></listitem>
f582cbca 445 </varlistentry>
f8b4ae29
LP
446
447 <varlistentry>
448 <term><varname>systemd.condition-needs-update=</varname></term>
449
450 <listitem><para>Takes a boolean argument. If specified, overrides the result of
451 <varname>ConditionNeedsUpdate=</varname> unit condition checks. See
452 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
453 details.</para></listitem>
454 </varlistentry>
814872e9
LP
455
456 <varlistentry>
457 <term><varname>systemd.condition-first-boot=</varname></term>
458
459 <listitem><para>Takes a boolean argument. If specified, overrides the result of
460 <varname>ConditionFirstBoot=</varname> unit condition checks. See
461 <citerefentry><refentrytitle>systemd.unit</refentrytitle><manvolnum>5</manvolnum></citerefentry> for
462 details. Not to be confused with <varname>systemd.firstboot=</varname> which only controls behaviour
463 of the <filename>systemd-firstboot.service</filename> system service but has no effect on the
464 condition check (see above).</para></listitem>
465 </varlistentry>
3753325b
LP
466
467 <varlistentry>
468 <term><varname>systemd.clock-usec=</varname></term>
469
470 <listitem><para>Takes a decimal, numeric timestamp in µs since January 1st 1970, 00:00am, to set the
18d9cee0
LP
471 system clock to. The system time is set to the specified timestamp early during boot. It is not
472 propagated to the hardware clock (RTC).</para></listitem>
473 </varlistentry>
474
475 <varlistentry>
476 <term><varname>systemd.random-seed=</varname></term>
477
478 <listitem><para>Takes a base64 encoded random seed value to credit with full entropy to the kernel's
479 random pool during early service manager initialization. This option is useful in testing
480 environments where delays due to random pool initialization in entropy starved virtual machines shall
481 be avoided.</para>
482
483 <para>Note that if this option is used the seed is accessible to unprivileged programs from
484 <filename>/proc/cmdline</filename>. This option is hence a security risk when used outside of test
485 systems, since the (possibly) only seed used for initialization of the kernel's entropy pool might be
486 easily acquired by unprivileged programs.</para>
487
488 <para>It is recommended to pass 512 bytes of randomized data (as that matches the Linux kernel pool
489 size), which may be generated with a command like the following:</para>
490
491 <programlisting>dd if=/dev/urandom bs=512 count=1 status=none | base64 -w 0</programlisting>
492
493 <para>Again: do not use this option outside of testing environments, it's a security risk elsewhere,
494 as secret key material derived from the entropy pool can possibly be reconstructed by unprivileged
495 programs.</para>
496 </listitem>
3753325b 497 </varlistentry>
34293dfa
LP
498
499 <varlistentry>
500 <term><varname>systemd.hostname=</varname></term>
501
502 <listitem><para>Accepts a hostname to set during early boot. If specified takes precedence over what
503 is set in <filename>/etc/hostname</filename>. Note that this does not bar later runtime changes to
504 the hostname, it simply controls the initial hostname set during early boot.</para></listitem>
505 </varlistentry>
798d3a52
ZJS
506 </variablelist>
507
508 </refsect1>
509
510 <refsect1>
511 <title>See Also</title>
512 <para>
513 <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
d1698b82 514 <citerefentry><refentrytitle>systemd-system.conf</refentrytitle><manvolnum>5</manvolnum></citerefentry>,
798d3a52 515 <citerefentry project='man-pages'><refentrytitle>bootparam</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
af105d03 516 <citerefentry project='man-pages'><refentrytitle>dracut.cmdline</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
798d3a52
ZJS
517 <citerefentry><refentrytitle>systemd-debug-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
518 <citerefentry><refentrytitle>systemd-fsck@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
519 <citerefentry><refentrytitle>systemd-quotacheck.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
520 <citerefentry><refentrytitle>systemd-journald.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
521 <citerefentry><refentrytitle>systemd-vconsole-setup.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
522 <citerefentry><refentrytitle>systemd-udevd.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
523 <citerefentry project='die-net'><refentrytitle>plymouth</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
524 <citerefentry><refentrytitle>systemd-cryptsetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
2f3dfc6f 525 <citerefentry><refentrytitle>systemd-veritysetup-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
798d3a52
ZJS
526 <citerefentry><refentrytitle>systemd-fstab-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
527 <citerefentry><refentrytitle>systemd-gpt-auto-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
91214a37 528 <citerefentry><refentrytitle>systemd-volatile-root.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
798d3a52
ZJS
529 <citerefentry><refentrytitle>systemd-modules-load.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
530 <citerefentry><refentrytitle>systemd-backlight@.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
af105d03 531 <citerefentry><refentrytitle>systemd-rfkill.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
f582cbca 532 <citerefentry><refentrytitle>systemd-hibernate-resume-generator</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
4e5aa791
ZJS
533 <citerefentry><refentrytitle>systemd-firstboot.service</refentrytitle><manvolnum>8</manvolnum></citerefentry>,
534 <citerefentry><refentrytitle>bootctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>
798d3a52
ZJS
535 </para>
536 </refsect1>
c66e7bc7
LP
537
538</refentry>