1GRUBBY(8) System Manager's Manual GRUBBY(8)
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6 grubby - command line tool for configuring grub and zipl
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10 grubby [--add-kernel=kernel-path] [--args=args]
11 [--bad-image-okay] [--config-file=path] [--copy-default]
12 [--default-kernel] [--default-index] [--default-title]
13 [--env=path] [--grub2] [--info=kernel-path]
14 [--initrd=initrd-path] [--extra-initrd=initrd-path]
15 [--make-default] [--remove-args=args]
16 [--remove-kernel=kernel-path] [--set-default=kernel-path]
17 [--set-default-index=entry-index] [--title=ntry-title]
18 [--update-kernel=kernel-path] [--zipl] [--bls-directory=path]
19
22 grubby is a command line tool for updating and displaying information
23 about the configuration files for the grub2 and zipl boot loaders. It
24 is primarily designed to be used from scripts which install new kernels
25 and need to find information about the current boot environment.
26 On BIOS-based Intel x86, PowerPC and UEFI-based platforms, grub2 is the
28 default bootloader and the configuration file is in
29 /boot/grub2/grub.cfg. On s390x platforms, the zipl bootloader use a
30 default configuration in /etc/zipl.conf.
31 All bootloaders define the boot entries as individual configuration
33 fragments that are stored by default in /boot/loader/entries. The for‐
34 mat for the config files is specified at https://sys‐
35 temd.io/BOOT_LOADER_SPECIFICATION. The grubby tool is used to update
36 and display the configuration defined in the BootLoaderSpec fragment
37 files.
38 There are a number of ways to specify the kernel used for --info, --re‐
40 move-kernel, and --update-kernel. Specificying DEFAULT or ALL selects
41 the default entry and all of the entries, respectively. Also, the ti‐
42 tle of a boot entry may be specified by using TITLE=title as the argu‐
43 ment; all entries with that title are used.
44
47 --add-kernel=kernel-path
48 Add a new boot entry for the kernel located at kernel-path.
49 --args=kernel-args
52 When a new kernel is added, this specifies the command line ar‐
53 guments which should be passed to the kernel by default (note
54 they are merged with the arguments of the default entry if
55 --copy-default is used). When --update-kernel is used, this
56 specifies new arguments to add to the argument list. Multiple,
57 space separated arguments may be used. If an argument already
58 exists the new value replaces the old values. The root= kernel
59 argument gets special handling if the configuration file has
60 special handling for specifying the root filesystem.
61 --bad-image-okay
64 When grubby is looking for an entry to use for something (such
65 as a default boot entry) it uses sanity checks, such as ensuring
66 that the kernel exists in the filesystem, to make sure entries
67 that obviously won't work aren't selected. This option overrides
68 that behavior, and is designed primarily for testing.
69 --config-file=path
72 Use path as the configuration file rather then the default.
73 --copy-default
76 grubby will copy as much information (such as kernel arguments
77 and root device) as possible from the current default kernel.
78 The kernel path and initrd path will never be copied.
79 --default-kernel
82 Display the full path to the current default kernel and exit.
83 --default-index
86 Display the numeric index of the current default boot entry and
87 exit.
88 --default-title
91 Display the title of the current default boot entry and exit.
92 --env=path
95 Use path as the grub2 environment block file rather then the de‐
96 fault path.
97 --grub2
100 Configure grub2 bootloader.
101 --info=kernel-path
104 Display information on all boot entries which match kernel-path.
105 If kernel-path is DEFAULT, then information on the default ker‐
106 nel is displayed. If kernel-path is ALL, then information on all
107 boot entries are displayed.
108 --initrd=initrd-path
111 Use initrd-path as the path to an initial ram disk for a new
112 kernel being added.
113 --extrainitrd=initrd-path
116 Use initrd-path as the path to an auxiliary init ram disk image
117 to be added to the boot entry.
118 --make-default
121 Make the new kernel entry being added the default entry.
122 --remove-args=kernel-args
125 The arguments specified by kernel-args are removed from the ker‐
126 nels specified by --update-kernel. The root argument gets spe‐
127 cial handling for configuration files that support separate root
128 filesystem configuration.
129 --remove-kernel=kernel-path
132 Removes all boot entries which match kernel-path. This may be
133 used along with --add-kernel, in which case the new kernel being
134 added will never be removed.
135 --set-default=kernel-path
138 The first entry which boots the specified kernel is made the de‐
139 fault boot entry.
140 --set-default-index=entry-index
143 Makes the given entry number the default boot entry.
144 --title=entry-title
147 When a new kernel entry is added entry-title is used as the ti‐
148 tle for the entry.
149 --update-kernel=kernel-path
152 The entries for kernels matching kernel-path are updated. Cur‐
153 rently the only items that can be updated is the kernel argument
154 list, which is modified via the --args and --remove-args op‐
155 tions. If the ALL argument is used the variable GRUB_CMD‐
156 LINE_LINUX in /etc/default/grub is updated with the latest ker‐
157 nel argument list, unless the --no-etc-grub-update option is
158 used.
159 --zipl Configure zipl bootloader.
162 --bls-directory=path
165 Use path as the directory for the BootLoaderSpec config files
166 rather than the default /boot/loader/entries.
167 --no-etc-grub-update
170 Makes grubby to not update the GRUB_CMDLINE_LINUX variable in
171 /etc/default/grub when the --update-kernel option is used with
172 the ALL argument.
173
176 zipl(8), mkinitrd(8), kernel-install(8)
177
180 Erik Troan
181 Jeremy Katz
182 Peter Jones
183 Javier Martinez
184 Wed Apr 29 2020 GRUBBY(8)