1GRUBBY(8)                   System Manager's Manual                  GRUBBY(8)
2
3
4

NAME

6       grubby  -  command  line tool used to configure bootloader menu entries
7       across multiple architectures
8
9

SYNOPSIS

11       grubby [OPTIONS]
12
13

DESCRIPTION

15   General Information
16       grubby is a command line tool for updating and  displaying  information
17       about  the  configuration files for various architecture specific boot‐
18       loaders.  It is primarily  designed  to  be  used  from  scripts  which
19       install new kernels and need to find information about the current boot
20       environment.
21
22
23   Architecture Support
24       The grubby executable has full support  for  the  grub2  bootloader  on
25       x86_64  systems using legacy BIOS or modern UEFI firmware and ppc64 and
26       ppc64le hardware using OPAL or SLOF as firmware.
27
28       Legacy s390 and the current s390x architectures and  their  zipl  boot‐
29       loader are fully supported.
30
31       Support for yaboot has been deprecated as all ppc architecture hardware
32       since the Power8 uses grub2 or petitboot which both use the grub2  con‐
33       figuration file format.
34
35       Legacy  bootloaders  LILO, SILO, and ELILO are deprecated and no longer
36       receiving active support in favor of previously mentioned bootloaders.
37
38
39   Default Behavior
40       The default bootloader target is primarily determined by the  architec‐
41       ture  for  which  grubby  has been built.  Each architecture has a pre‐
42       ferred bootloader, and each bootloader has its own configuration  file.
43       If no bootloader is selected on the command line, grubby will use these
44       default settings to search for an existing configuration.  If no  boot‐
45       loader  configuration  file is found, grubby will use the default value
46       for that architecture.  These defaults are listed in the table below.
47
48
49       ┌────────────────┬────────────┬─────────────────────────────────┐
50Arch           Bootloader Configuration File              
51       ├────────────────┼────────────┼─────────────────────────────────┤
52       │ x86_64 [BIOS]  │ grub2      │ /boot/grub2/grub.cfg            │
53       ├────────────────┼────────────┼─────────────────────────────────┤
54       │ x86_64 [UEFI]  │ grub2      │ /boot/efi/EFI/redhat/grub.cfg   │
55       ├────────────────┼────────────┼─────────────────────────────────┤
56       │ i386           │ grub2      │ /boot/grub2/grub.cfg            │
57       ├────────────────┼────────────┼─────────────────────────────────┤
58       │ ia64           │ elilo      │ /boot/efi/EFI/redhat/elilo.conf │
59       ├────────────────┼────────────┼─────────────────────────────────┤
60       │ ppc [>=Power8] │ grub2      │ /boot/grub2/grub.cfg            │
61       ├────────────────┼────────────┼─────────────────────────────────┤
62       │ ppc [<=Power7] │ yaboot     │ /etc/yaboot.conf                │
63       ├────────────────┼────────────┼─────────────────────────────────┤
64       │ s390           │ zipl       │ /etc/zipl.conf                  │
65       ├────────────────┼────────────┼─────────────────────────────────┤
66       │ s390x          │ zipl       │ /etc/zipl.conf                  │
67       └────────────────┴────────────┴─────────────────────────────────┘
68
69
70   Special Arguments
71       There are a number of ways to  specify  the  kernel  used  for  --info,
72       --remove-kernel, and --update-kernel. Specifying DEFAULT or ALL selects
73       the default entry and all of the entries,  respectively.   If  a  comma
74       separated  list  of numbers is given, the boot entries indexed by those
75       numbers are selected. Finally, the title of a boot entry may be  speci‐
76       fied  by using TITLE=title as the argument; all entries with that title
77       are used.
78
79

OPTIONS

81   Basic Options
82       --add-kernel=kernel-path
83              Add a new boot entry for the kernel located  at  kernel-path.  A
84              title for the boot entry must be set using --title. Most invoca‐
85              tions should also include --initrd with memtest86 as  a  notable
86              exception.
87
88              The  --update-kernel  option may not be used in the same invoca‐
89              tion.
90
91
92       --remove-kernel=kernel-path
93              Remove all boot entries which match  kernel-path.  This  may  be
94              used  along with --add-kernel, in which case the new entry being
95              added will not be removed.
96
97
98       --update-kernel=kernel-path
99              Update the entries for kernels matching  kernel-path.  Currently
100              the  only  item that can be updated is the kernel argument list,
101              which is modified via the --args and --remove-args options.
102
103
104       --args=kernel-args
105              When a new kernel is added,  this  specifies  the  command  line
106              arguments  which should be passed to the kernel by default (note
107              they are merged with the arguments from the template if  --copy-
108              default  is used).  When --update-kernel is used, this specifies
109              new arguments to add to the argument list. Multiple, space sepa‐
110              rated  arguments  may be used. If an argument already exists the
111              new value replaces the old values.  The  root=  kernel  argument
112              gets special handling if the configuration file has special han‐
113              dling for specifying the root filesystem (like lilo.conf does).
114
115
116       --remove-args=kernel-args
117              The arguments specified by kernel-args are removed from the ker‐
118              nels  specified  by --update-kernel. The root argument gets spe‐
119              cial handling for configuration files that support separate root
120              filesystem configuration.
121
122
123       --copy-default
124              grubby  will  copy as much information (such as kernel arguments
125              and root device) as possible from the  current  default  kernel.
126              The kernel path and initrd path will never be copied.
127
128
129       --title=entry-title
130              When  a  new  kernel  entry  is added entry-title is used as the
131              title (lilo label) for the entry. If entry-title is longer  then
132              maximum length allowed by the bootloader (15 for lilo, unlimited
133              for grub and elilo) the title is shortened to a (unique) entry.
134
135
136       --initrd=initrd-path
137              Use initrd-path as the path to an initial ram  disk  for  a  new
138              kernel being added.
139
140
141       --efi  Use  appropriate  bootloader  commands for EFI on this architec‐
142              ture.
143
144
145       --set-default=kernel-path
146              The first entry which boots the specified  kernel  is  made  the
147              default  boot entry. This may not be invoked with --set-default-
148              index.
149
150
151       --set-default-index=entry-index
152              Makes the given entry number the default boot  entry.  This  may
153              not  be  invoked with --set-default.  The given value represents
154              the index in the post-modification boot entry list.
155
156
157       --make-default
158              Make the new kernel entry being added the default entry.
159
160
161       --set-index=entry-index
162              Set the position at which to add a new entry created with --add-
163              kernel.
164
165
166       --debug
167              Display extra debugging information for failures.
168
169
170       -i, --extra-initrd=initrd-path
171              Use initrd-path as the path for an auxiliary initrd image.
172
173
174   Display Options
175       Passing  the  display  option  to grubby will cause it to print out the
176       requested information about the current  bootloader  configuration  and
177       then  immediately exit.  These options should not be used in any script
178       intended to update the bootloader configuration.
179
180
181       --default-kernel
182              Display the full path to the current default kernel and exit.
183
184
185       --default-index
186              Display the numeric index of the current default boot entry  and
187              exit.
188
189
190       --default-title
191              Display the title of the current default boot entry and exit.
192
193
194       --info=kernel-path
195              Display information on all boot entries which match kernel-path.
196              If kernel-path is DEFAULT, then information on the default  ker‐
197              nel is displayed. If kernel-path is ALL, then information on all
198              boot entries are displayed.
199
200
201       --bootloader-probe
202              Attempt to probe for installed bootloaders.  If this  option  is
203              specified,  grubby  tries  to  determine if grub or lilo is cur‐
204              rently installed. When one of those  bootloaders  is  found  the
205              name  of  that bootloader is displayed on stdout.  Both could be
206              installed (on different devices), and grubby will print out  the
207              names  of  both  bootloaders,  one  per line. The probe for grub
208              requires a commented out boot directive grub.conf  identical  to
209              the  standard  directive in the lilo configuration file. If this
210              is not present grubby will assume grub is  not  installed  (note
211              that  anaconda  places this directive in grub.conf files it cre‐
212              ates).
213
214              This option is only available on x86 BIOS platforms.
215
216
217       -v, --version
218              Display the version of grubby being run and  then  exit  immedi‐
219              ately.
220
221
222   Output Format Options
223       Sane  default options for the current platform are compiled into grubby
224       on a per platform basis. These defaults determine the format and layout
225       of  the generated bootloader configuration file. A different configura‐
226       tion file format may be specified on the command  line  if  the  system
227       uses a supported alternative bootloader.
228
229
230       --elilo
231              Use  an  elilo  style configuration file. This is the default on
232              ia64 platforms. This format is deprecated.
233
234
235       --extlinux
236              Use an extlinux style configuration file. This format is  depre‐
237              cated.
238
239
240       --grub Use  a grub style configuration file. This is the default on the
241              i386 architecture.
242
243
244       --grub2
245              Use a grub2 style configuration file. This  is  the  default  on
246              x86_64  architecture  as well as the ppc64 and ppc64le architec‐
247              tures running on Power8 or later hardware.
248
249
250       --lilo Use a lilo style configuration file.
251
252
253       --silo Use a silo style configuration file.  This  is  the  default  on
254              SPARC  systems.  This  format  is legacy, deprecated, and unsup‐
255              ported.
256
257
258       --yaboot
259              Use a yaboot style configuration file. This is the  default  for
260              the ppc architecture on on Power7 and earlier hardware.
261
262
263       --zipl Use  a zipl style configuration file. This is the default on the
264              legacy s390 and current s390x architectures.
265
266
267   Override Options
268       --bad-image-okay
269              When grubby is looking for a entry to use for something (such as
270              a  template or a default boot entry) it uses sanity checks, such
271              as ensuring that the kernel exists in the  filesystem,  to  make
272              sure  entries  that  obviously  won't work aren't selected. This
273              option overrides that behavior, and is  designed  primarily  for
274              testing.
275
276
277       --boot-filesystem=bootfs
278              The grub boot loader expects file paths listed in its configura‐
279              tion path to be relative to the top of the filesystem  they  are
280              on,  rather  then  relative  to  the current root filesystem. By
281              default grubby searches the list of currently  mounted  filesys‐
282              tems  to  determine this. If this option is given grubby acts as
283              if the specified filesystem was the  filesystem  containing  the
284              kernel (this option is designed primarily for testing).
285
286
287       --env=path
288              Path for the file where grub environment data is stored.
289
290
291       -c, --config-file=path
292              Use path as the configuration file rather then the default.
293
294
295       -o, --output-file=file_path
296              The destination path for the updated configuration file. Use "-"
297              to send it to stdout.
298
299
300       --devtree=file_path
301              Use path for device tree path  in  place  of  the  path  of  any
302              devicetree directive found in the template stanza.
303
304
305       --devtreedir=file_path
306              Use  the  specified file path to load the devicetree definition.
307              This is for platforms where a  flat  file  is  used  instead  of
308              firmware to instruct the kernel how to communicate with devices.
309
310
311   Multiboot Options
312       The Multiboot Specification provides a generic interface for boot load‐
313       ers and operating systems.  It is supported by the GRUB bootloader.
314
315
316       --add-multiboot=multiboot-path
317              Add a new boot entry for the multiboot kernel located at  multi‐
318              boot-path.   Note  that  this  is  generally  accompanied with a
319              --add-kernel option.
320
321
322       --remove-multiboot=multiboot-path
323              Removes all boot entries which match multiboot-path.
324
325
326       --mbargs=multiboot-args
327              When a new multiboot kernel is added, this specifies the command
328              line  arguments which should be passed to that kernel by default
329              When --update-kernel is used, this specifies  new  arguments  to
330              add  to  the  argument list. Multiple, space separated arguments
331              may be used.  If  an  argument  already  exists  the  new  value
332              replaces the old values.
333
334
335       --remove-mbargs=multiboot-args
336              The  arguments  specified by multiboot-args are removed from the
337              kernels specified by --update-kernel.
338
339

BUGS

341       The command line syntax is more than a little  baroque.  This  probably
342       won't  be  fixed  as  grubby  is  only intended to be called from shell
343       scripts which can get it right.
344
345

EXAMPLE

347       The following examples assume the following:
348
349
350       ┌────────────────┬─────────────────────────────────────────────┐
351cfg_file │ Full path to bootloader config file         │
352       ├────────────────┼─────────────────────────────────────────────┤
353new_kernel │ Full path to kernel image to be installed   │
354       ├────────────────┼─────────────────────────────────────────────┤
355old_kernel │ Full path to old kernel image to be removed │
356       ├────────────────┼─────────────────────────────────────────────┤
357current_kernel │ Full path to a currently installed kernel   │
358       ├────────────────┼─────────────────────────────────────────────┤
359entry_title │ Title that appears on bootloader menu       │
360       ├────────────────┼─────────────────────────────────────────────┤
361new_initrd │ Full path to initrd for a new kernel        │
362       ├────────────────┼─────────────────────────────────────────────┤
363kernel_args │ Set of arguments for the kernel             │
364       ├────────────────┼─────────────────────────────────────────────┤
365menu_index │ Index number of a menu entry                │
366       └────────────────┴─────────────────────────────────────────────┘
367       The examples below quote strings that may have spaces or  other  white‐
368       space  in  them.  It  is also perfectly valid to backslash escape these
369       strings if that is more convenient.
370
371
372       Add a new kernel entry and copy all options from  the  current  default
373       kernel.  This is the behavior that most users will want.
374
375              grubby   --add-kernel=new_kernel   --title="entry_title"  --ini‐
376              trd="new_initrd" --copy-default
377
378       Add a new kernel entry with custom arguments
379
380              grubby  --add-kernel=new_kernel   --title="entry_title"   --ini‐
381              trd="new_initrd" --args=kernel_args
382
383       Remove all menu entries for a specified kernel.
384
385              grubby --remove-kernel=old_kernel
386
387       Target  a  single menu entry to remove without targetting other entries
388       with the same kernel.
389
390              grubby --info=old_kernel
391
392              grubby --remove-kernel=menu_index
393
394       Update the arguments for all entries of a specific  kernel.  New  argu‐
395       ments get added while existing arguments get updated values.
396
397              grubby --update-kernel=current_kernel --args="kernel_args"
398
399       Remove the arguments for a single entry of a specific kernel.
400
401              grubby --info=current_kernel
402
403              grubby --remove-args=menu_index --args="kernel_args"
404
405

SEE ALSO

407       grub(8), lilo(8), yaboot(8), zipl(8), dracut(8), mkinitrd(8)
408
409

AUTHORS

411       Erik Troan
412       Jeremy Katz
413       Peter Jones
414       Robert Marshall
415
416
417
418                                Tue Jan 18 2005                      GRUBBY(8)
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