Next:, Up: [][] GNU GRUB manual This is the documentation of GNU GRUB, the GRand Unified Bootloader, a flexible and powerful boot loader program for a wide range of architectures. This edition documents version 2.02.

This manual is for GNU GRUB (version 2.02, 25 April 2017). Copyright © 1999,2000,2001,2002,2004,2006,2008,2009,2010,2011,2012,2013 Free Software Foundation, Inc. Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections. Next:, Up: [][] 1.1 Overview Briefly, a boot loader is the first software program that runs when a computer starts. It is responsible for loading and transferring control to an operating system kernel software (such as Linux or GNU Mach). The kernel, in turn, initializes the rest of the operating system (e.g. A GNU system).

Sometimes we have pdf's that we need to edit and to do so we can use apps like Inkscape (which we already saw on a previous article) or GIMP. When you edit them with Inkscape, you have the advantage that the imported content will remain as vector (except those attached images that will remain as.

GNU GRUB is a very powerful boot loader, which can load a wide variety of free operating systems, as well as proprietary operating systems with chain-loading. GRUB is designed to address the complexity of booting a personal computer; both the program and this manual are tightly bound to that computer platform, although porting to other platforms may be addressed in the future. One of the important features in GRUB is flexibility; GRUB understands filesystems and kernel executable formats, so you can load an arbitrary operating system the way you like, without recording the physical position of your kernel on the disk.

Thus you can load the kernel just by specifying its file name and the drive and partition where the kernel resides. When booting with GRUB, you can use either a command-line interface (see ), or a menu interface (see ). Using the command-line interface, you type the drive specification and file name of the kernel manually. In the menu interface, you just select an OS using the arrow keys. The menu is based on a configuration file which you prepare beforehand (see ). While in the menu, you can switch to the command-line mode, and vice-versa.

You can even edit menu entries before using them. In the following chapters, you will learn how to specify a drive, a partition, and a file name (see ) to GRUB, how to install GRUB on your drive (see ), and how to boot your OSes (see ), step by step. Next:, Previous:, Up: [][] 1.2 History of GRUB GRUB originated in 1995 when Erich Boleyn was trying to boot the GNU Hurd with the University of Utah’s Mach 4 microkernel (now known as GNU Mach). Erich and Brian Ford designed the Multiboot Specification (see in The Multiboot Specification), because they were determined not to add to the large number of mutually-incompatible PC boot methods. Erich then began modifying the FreeBSD boot loader so that it would understand Multiboot. He soon realized that it would be a lot easier to write his own boot loader from scratch than to keep working on the FreeBSD boot loader, and so GRUB was born. Erich added many features to GRUB, but other priorities prevented him from keeping up with the demands of its quickly-expanding user base.

In 1999, Gordon Matzigkeit and Yoshinori K. Okuji adopted GRUB as an official GNU package, and opened its development by making the latest sources available via anonymous CVS. See, for more information.

Over the next few years, GRUB was extended to meet many needs, but it quickly became clear that its design was not keeping up with the extensions being made to it, and we reached the point where it was very difficult to make any further changes without breaking existing features. Around 2002, Yoshinori K. Okuji started work on PUPA (Preliminary Universal Programming Architecture for GNU GRUB), aiming to rewrite the core of GRUB to make it cleaner, safer, more robust, and more powerful. PUPA was eventually renamed to GRUB 2, and the original version of GRUB was renamed to GRUB Legacy. Small amounts of maintenance continued to be done on GRUB Legacy, but the last release (0.97) was made in 2005 and at the time of writing it seems unlikely that there will be another. By around 2007, GNU/Linux distributions started to use GRUB 2 to limited extents, and by the end of 2009 multiple major distributions were installing it by default.

Next:, Previous:, Up: [][] 1.3 Differences from previous versions GRUB 2 is a rewrite of GRUB (see ), although it shares many characteristics with the previous version, now known as GRUB Legacy. Users of GRUB Legacy may need some guidance to find their way around this new version. • The configuration file has a new name ( grub.cfg rather than menu.lst or grub.conf), new syntax (see ) and many new commands (see ). Configuration cannot be copied over directly, although most GRUB Legacy users should not find the syntax too surprising.

• grub.cfg is typically automatically generated by grub-mkconfig (see ). This makes it easier to handle versioned kernel upgrades. • Partition numbers in GRUB device names now start at 1, not 0 (see ).

• The configuration file is now written in something closer to a full scripting language: variables, conditionals, and loops are available. • A small amount of persistent storage is available across reboots, using the save_env and load_env commands in GRUB and the grub-editenv utility. This is not available in all configurations (see ). • GRUB 2 has more reliable ways to find its own files and those of target kernels on multiple-disk systems, and has commands (see ) to find devices using file system labels or Universally Unique Identifiers (UUIDs). • GRUB 2 is available for several other types of system in addition to the PC BIOS systems supported by GRUB Legacy: PC EFI, PC coreboot, PowerPC, SPARC, and MIPS Lemote Yeeloong are all supported. • Many more file systems are supported, including but not limited to ext4, HFS+, and NTFS. • GRUB 2 can read files directly from LVM and RAID devices.

• A graphical terminal and a graphical menu system are available. • GRUB 2’s interface can be translated, including menu entry names. • The image files (see ) that make up GRUB have been reorganised; Stage 1, Stage 1.5, and Stage 2 are no more. • GRUB 2 puts many facilities in dynamically loaded modules, allowing the core image to be smaller, and allowing the core image to be built in more flexible ways. Next:, Previous:, Up: [][] 1.4 GRUB features The primary requirement for GRUB is that it be compliant with the Multiboot Specification, which is described in in The Multiboot Specification. The other goals, listed in approximate order of importance, are: • Basic functions must be straightforward for end-users. • Rich functionality to support kernel experts and designers.

• Backward compatibility for booting FreeBSD, NetBSD, OpenBSD, and Linux. Proprietary kernels (such as DOS, Windows NT, and OS/2) are supported via a chain-loading function. Except for specific compatibility modes (chain-loading and the Linux piggyback format), all kernels will be started in much the same state as in the Multiboot Specification.

Only kernels loaded at 1 megabyte or above are presently supported. Any attempt to load below that boundary will simply result in immediate failure and an error message reporting the problem. In addition to the requirements above, GRUB has the following features (note that the Multiboot Specification doesn’t require all the features that GRUB supports): Recognize multiple executable formats Support many of the a.out variants plus ELF. Symbol tables are also loaded. Support non-Multiboot kernels Support many of the various free 32-bit kernels that lack Multiboot compliance (primarily FreeBSD, NetBSD, OpenBSD, and Linux).

Chain-loading of other boot loaders is also supported. Load multiples modules Fully support the Multiboot feature of loading multiple modules. Load a configuration file Support a human-readable text configuration file with preset boot commands. You can also load another configuration file dynamically and embed a preset configuration file in a GRUB image file. The list of commands (see ) are a superset of those supported on the command-line.

An example configuration file is provided in. Provide a menu interface A menu interface listing preset boot commands, with a programmable timeout, is available. There is no fixed limit on the number of boot entries, and the current implementation has space for several hundred. Have a flexible command-line interface A fairly flexible command-line interface, accessible from the menu, is available to edit any preset commands, or write a new boot command set from scratch. If no configuration file is present, GRUB drops to the command-line.

The list of commands (see ) are a subset of those supported for configuration files. Editing commands closely resembles the Bash command-line (see in Bash Features), with TAB-completion of commands, devices, partitions, and files in a directory depending on context. Support multiple filesystem types Support multiple filesystem types transparently, plus a useful explicit blocklist notation. The currently supported filesystem types are Amiga Fast FileSystem (AFFS), AtheOS fs, BeFS, BtrFS (including raid0, raid1, raid10, gzip and lzo), cpio (little- and big-endian bin, odc and newc variants), Linux ext2/ext3/ext4, DOS FAT12/FAT16/FAT32, exFAT, HFS, HFS+, ISO9660 (including Joliet, Rock-ridge and multi-chunk files), JFS, Minix fs (versions 1, 2 and 3), nilfs2, NTFS (including compression), ReiserFS, ROMFS, Amiga Smart FileSystem (SFS), Squash4, tar, UDF, BSD UFS/UFS2, XFS, and ZFS (including lzjb, gzip, zle, mirror, stripe, raidz1/2/3 and encryption in AES-CCM and AES-GCM). See, for more information.

Support automatic decompression Can decompress files which were compressed by gzip or xz. This function is both automatic and transparent to the user (i.e.

All functions operate upon the uncompressed contents of the specified files). This greatly reduces a file size and loading time, a particularly great benefit for floppies. It is conceivable that some kernel modules should be loaded in a compressed state, so a different module-loading command can be specified to avoid uncompressing the modules. Access data on any installed device Support reading data from any or all floppies or hard disk(s) recognized by the BIOS, independent of the setting of the root device. Be independent of drive geometry translations Unlike many other boot loaders, GRUB makes the particular drive translation irrelevant.

A drive installed and running with one translation may be converted to another translation without any adverse effects or changes in GRUB’s configuration. Detect all installed RAM GRUB can generally find all the installed RAM on a PC-compatible machine. It uses an advanced BIOS query technique for finding all memory regions. As described on the Multiboot Specification (see in The Multiboot Specification), not all kernels make use of this information, but GRUB provides it for those who do. Support Logical Block Address mode In traditional disk calls (called CHS mode), there is a geometry translation problem, that is, the BIOS cannot access over 1024 cylinders, so the accessible space is limited to at least 508 MB and to at most 8GB.

GRUB can’t universally solve this problem, as there is no standard interface used in all machines. However, several newer machines have the new interface, Logical Block Address ( LBA) mode. GRUB automatically detects if LBA mode is available and uses it if available.

In LBA mode, GRUB can access the entire disk. Support network booting GRUB is basically a disk-based boot loader but also has network support. You can load OS images from a network by using the TFTP protocol. Support remote terminals To support computers with no console, GRUB provides remote terminal support, so that you can control GRUB from a remote host. Only serial terminal support is implemented at the moment. Previous:, Up: [][] 1.5 The role of a boot loader The following is a quotation from Gordon Matzigkeit, a GRUB fanatic: Some people like to acknowledge both the operating system and kernel when they talk about their computers, so they might say they use “GNU/Linux” or “GNU/Hurd”. Other people seem to think that the kernel is the most important part of the system, so they like to call their GNU operating systems “Linux systems.” I, personally, believe that this is a grave injustice, because the boot loader is the most important software of all.

I used to refer to the above systems as either “LILO” or “GRUB” systems. Unfortunately, nobody ever understood what I was talking about; now I just use the word “GNU” as a pseudonym for GRUB. So, if you ever hear people talking about their alleged “GNU” systems, remember that they are actually paying homage to the best boot loader around GRUB! We, the GRUB maintainers, do not (usually) encourage Gordon’s level of fanaticism, but it helps to remember that boot loaders deserve recognition.

We hope that you enjoy using GNU GRUB as much as we did writing it. (hd0,msdos2) Here, ‘ hd’ means it is a hard disk drive. The first integer ‘ 0’ indicates the drive number, that is, the first hard disk, the string ‘ msdos’ indicates the partition scheme, while the second integer, ‘ 2’, indicates the partition number (or the PC slice number in the BSD terminology). The partition numbers are counted from one, not from zero (as was the case in previous versions of GRUB). This expression means the second partition of the first hard disk drive.

In this case, GRUB uses one partition of the disk, instead of the whole disk. Set root=( followed by a TAB, and GRUB will display the list of drives, partitions, or file names. So it should be quite easy to determine the name of your target partition, even with minimal knowledge of the syntax. Note that GRUB does not distinguish IDE from SCSI - it simply counts the drive numbers from zero, regardless of their type. Normally, any IDE drive number is less than any SCSI drive number, although that is not true if you change the boot sequence by swapping IDE and SCSI drives in your BIOS. Now the question is, how to specify a file?

Again, consider an example. Next:, Previous:, Up: [][] 4 Installation In order to install GRUB as your boot loader, you need to first install the GRUB system and utilities under your UNIX-like operating system (see ).

You can do this either from the source tarball, or as a package for your OS. After you have done that, you need to install the boot loader on a drive (floppy or hard disk) by using the utility grub-install (see ) on a UNIX-like OS. GRUB comes with boot images, which are normally put in the directory /usr/lib/grub/- (for BIOS-based machines /usr/lib/grub/i386-pc). Hereafter, the directory where GRUB images are initially placed (normally /usr/lib/grub/-) will be called the image directory, and the directory where the boot loader needs to find them (usually /boot) will be called the boot directory. Next:, Up: [][] 4.1 Installing GRUB using grub-install For information on where GRUB should be installed on PC BIOS platforms, see. In order to install GRUB under a UNIX-like OS (such as GNU), invoke the program grub-install (see ) as the superuser ( root). The usage is basically very simple.

You only need to specify one argument to the program, namely, where to install the boot loader. The argument has to be either a device file (like ‘ /dev/hda’). For example, under Linux the following will install GRUB into the MBR of the first IDE disk. # losetup /dev/loop0 /dev/sdb1 # mount /dev/loop0 /mnt/usb # grub-install --boot-directory=/mnt/usb/bugbios --force --allow-floppy /dev/loop0 This install doesn’t conflict with standard install as long as they are in separate directories. Note that grub-install is actually just a shell script and the real task is done by other tools such as grub-mkimage.

Therefore, you may run those commands directly to install GRUB, without using grub-install. Don’t do that, however, unless you are very familiar with the internals of GRUB. Installing a boot loader on a running OS may be extremely dangerous. On EFI systems for fixed disk install you have to mount EFI System Partition. If you mount it at /boot/efi then you don’t need any special arguments. Next:, Previous:, Up: [][] 4.2 Making a GRUB bootable CD-ROM GRUB supports the no emulation mode in the El Torito specification.

This means that you can use the whole CD-ROM from GRUB and you don’t have to make a floppy or hard disk image file, which can cause compatibility problems. For booting from a CD-ROM, GRUB uses a special image called cdboot.img, which is concatenated with core.img. The core.img used for this should be built with at least the ‘ iso9660’ and ‘ biosdisk’ modules. Your bootable CD-ROM will usually also need to include a configuration file grub.cfg and some other GRUB modules.

To make a simple generic GRUB rescue CD, you can use the grub-mkrescue program (see ). ( device) file device is a drive specified in the GRUB syntax (see ), and file is an OS file, which is normally a device file. Historically, the device map file was used because GRUB device names had to be used in the configuration file, and they were derived from BIOS drive numbers. The map between BIOS drives and OS devices cannot always be guessed correctly: for example, GRUB will get the order wrong if you exchange the boot sequence between IDE and SCSI in your BIOS. Unfortunately, even OS device names are not always stable. Modern versions of the Linux kernel may probe drives in a different order from boot to boot, and the prefix ( /dev/hd* versus /dev/sd*) may change depending on the driver subsystem in use.

As a result, the device map file required frequent editing on some systems. GRUB avoids this problem nowadays by using UUIDs or file system labels when generating grub.cfg, and we advise that you do the same for any custom menu entries you write. If the device map file does not exist, then the GRUB utilities will assume a temporary device map on the fly. This is often good enough, particularly in the common case of single-disk systems. However, the device map file is not entirely obsolete yet, and it is used for overriding when current environment is different from the one on boot. Most common case is if you use a partition or logical volume as a disk for virtual machine.

You can put any comments in the file if needed, as the GRUB utilities assume that a line is just a comment if the first character is ‘ #’. Previous:, Up: [][] 4.4 BIOS installation MBR The partition table format traditionally used on PC BIOS platforms is called the Master Boot Record (MBR) format; this is the format that allows up to four primary partitions and additional logical partitions. With this partition table format, there are two ways to install GRUB: it can be embedded in the area between the MBR and the first partition (called by various names, such as the 'boot track', 'MBR gap', or 'embedding area', and which is usually at least 31 KiB), or the core image can be installed in a file system and a list of the blocks that make it up can be stored in the first sector of that partition.

Each of these has different problems. There is no way to reserve space in the embedding area with complete safety, and some proprietary software is known to use it to make it difficult for users to work around licensing restrictions; and systems are sometimes partitioned without leaving enough space before the first partition. On the other hand, installing to a filesystem means that GRUB is vulnerable to its blocks being moved around by filesystem features such as tail packing, or even by aggressive fsck implementations, so this approach is quite fragile; and this approach can only be used if the /boot filesystem is on the same disk that the BIOS boots from, so that GRUB does not have to rely on guessing BIOS drive numbers. The GRUB development team generally recommends embedding GRUB before the first partition, unless you have special requirements. You must ensure that the first partition starts at least 31 KiB (63 sectors) from the start of the disk; on modern disks, it is often a performance advantage to align partitions on larger boundaries anyway, so the first partition might start 1 MiB from the start of the disk. GPT Some newer systems use the GUID Partition Table (GPT) format. This was specified as part of the Extensible Firmware Interface (EFI), but it can also be used on BIOS platforms if system software supports it; for example, GRUB and GNU/Linux can be used in this configuration.

With this format, it is possible to reserve a whole partition for GRUB, called the BIOS Boot Partition. GRUB can then be embedded into that partition without the risk of being overwritten by other software and without being contained in a filesystem which might move its blocks around. When creating a BIOS Boot Partition on a GPT system, you should make sure that it is at least 31 KiB in size.

(GPT-formatted disks are not usually particularly small, so we recommend that you make it larger than the bare minimum, such as 1 MiB, to allow plenty of room for growth.) You must also make sure that it has the proper partition type. Using GNU Parted, you can set this using a command such as the following. Next:, Up: [][] 5.1 How to boot operating systems GRUB has two distinct boot methods. One of the two is to load an operating system directly, and the other is to chain-load another boot loader which then will load an operating system actually. Generally speaking, the former is more desirable, because you don’t need to install or maintain other boot loaders and GRUB is flexible enough to load an operating system from an arbitrary disk/partition.

However, the latter is sometimes required, since GRUB doesn’t support all the existing operating systems natively. Next:, Up: [][] 5.1.1 How to boot an OS directly with GRUB Multiboot (see in The Multiboot Specification) is the native format supported by GRUB. For the sake of convenience, there is also support for Linux, FreeBSD, NetBSD and OpenBSD. If you want to boot other operating systems, you will have to chain-load them (see ). FIXME: this section is incomplete. • Run the command boot (see ).

However, DOS and Windows have some deficiencies, so you might have to use more complicated instructions. See, for more information. Next:, Previous:, Up: [][] 5.2 Loopback booting GRUB is able to read from an image (be it one of CD or HDD) stored on any of its accessible storages (refer to see command). However the OS itself should be able to find its root. This usually involves running a userspace program running before the real root is discovered. This is achieved by GRUB loading a specially made small image and passing it as ramdisk to the kernel.

This is achieved by commands kfreebsd_module, knetbsd_module_elf, kopenbsd_ramdisk, initrd (see ), initrd16 (see ), multiboot_module, multiboot2_module or xnu_ramdisk depending on the loader. Note that for knetbsd the image must be put inside miniroot.kmod and the whole miniroot.kmod has to be loaded. In kopenbsd payload this is disabled by default.

Aditionally behaviour of initial ramdisk depends on command line options. Several distributors provide the image for this purpose or it’s integrated in their standard ramdisk and activated by special option. Consult your kernel and distribution manual for more details.

Other loaders like appleloader, chainloader (BIOS, EFI, coreboot), freedos, ntldr and plan9 provide no possibility of loading initial ramdisk and as far as author is aware the payloads in question don’t support either initial ramdisk or discovering loopback boot in other way and as such not bootable this way. Please consider alternative boot methods like copying all files from the image to actual partition. Consult your OS documentation for more details. Previous:, Up: [][] 5.3.4 DOS/Windows GRUB cannot boot DOS or Windows directly, so you must chain-load them (see ).

However, their boot loaders have some critical deficiencies, so it may not work to just chain-load them. To overcome the problems, GRUB provides you with two helper functions. If you have installed DOS (or Windows) on a non-first hard disk, you have to use the disk swapping technique, because that OS cannot boot from any disks but the first one. The workaround used in GRUB is the command drivemap (see ), like this. Drivemap -s (hd0) (hd1) This performs a virtual swap between your first and second hard drive.

Caution: This is effective only if DOS (or Windows) uses BIOS to access the swapped disks. If that OS uses a special driver for the disks, this probably won’t work. Another problem arises if you installed more than one set of DOS/Windows onto one disk, because they could be confused if there are more than one primary partitions for DOS/Windows. Certainly you should avoid doing this, but there is a solution if you do want to do so. Use the partition hiding/unhiding technique. If GRUB hides a DOS (or Windows) partition (see ), DOS (or Windows) will ignore the partition.

If GRUB unhides a DOS (or Windows) partition, DOS (or Windows) will detect the partition. Thus, if you have installed DOS (or Windows) on the first and the second partition of the first hard disk, and you want to boot the copy on the first partition, do the following. Next:, Up: [][] 6.1 Simple configuration handling The program grub-mkconfig (see ) generates grub.cfg files suitable for most cases. It is suitable for use when upgrading a distribution, and will discover available kernels and attempt to generate menu entries for them. Grub-mkconfig does have some limitations. While adding extra custom menu entries to the end of the list can be done by editing /etc/grub.d/40_custom or creating /boot/grub/custom.cfg, changing the order of menu entries or changing their titles may require making complex changes to shell scripts stored in /etc/grub.d/. This may be improved in the future.

In the meantime, those who feel that it would be easier to write grub.cfg directly are encouraged to do so (see, and ), and to disable any system provided by their distribution to automatically run grub-mkconfig. The file /etc/default/grub controls the operation of grub-mkconfig. It is sourced by a shell script, and so must be valid POSIX shell input; normally, it will just be a sequence of ‘ KEY=value’ lines, but if the value contains spaces or other special characters then it must be quoted. GRUB_DEFAULT=example-gnu-linux Previously it was documented the way to use entry title. While this still works it’s not recommended since titles often contain unstable device names and may be translated If you set this to ‘ saved’, then the default menu entry will be that saved by ‘ GRUB_SAVEDEFAULT’ or grub-set-default. This relies on the environment block, which may not be available in all situations (see ). The default is ‘ 0’.

‘ GRUB_SAVEDEFAULT’ If this option is set to ‘ true’, then, when an entry is selected, save it as a new default entry for use by future runs of GRUB. This is only useful if ‘ GRUB_DEFAULT=saved’; it is a separate option because ‘ GRUB_DEFAULT=saved’ is useful without this option, in conjunction with grub-set-default. Unset by default. This option relies on the environment block, which may not be available in all situations (see ). ‘ GRUB_TIMEOUT’ Boot the default entry this many seconds after the menu is displayed, unless a key is pressed. The default is ‘ 5’.

Set to ‘ 0’ to boot immediately without displaying the menu, or to ‘ -1’ to wait indefinitely. If ‘ GRUB_TIMEOUT_STYLE’ is set to ‘ countdown’ or ‘ hidden’, the timeout is instead counted before the menu is displayed. ‘ GRUB_TIMEOUT_STYLE’ If this option is unset or set to ‘ menu’, then GRUB will display the menu and then wait for the timeout set by ‘ GRUB_TIMEOUT’ to expire before booting the default entry. Pressing a key interrupts the timeout. If this option is set to ‘ countdown’ or ‘ hidden’, then, before displaying the menu, GRUB will wait for the timeout set by ‘ GRUB_TIMEOUT’ to expire. If ESC is pressed during that time, it will display the menu and wait for input.

If a hotkey associated with a menu entry is pressed, it will boot the associated menu entry immediately. If the timeout expires before either of these happens, it will boot the default entry. In the ‘ countdown’ case, it will show a one-line indication of the remaining time. ‘ GRUB_DEFAULT_BUTTON’ ‘ GRUB_TIMEOUT_BUTTON’ ‘ GRUB_TIMEOUT_STYLE_BUTTON’ ‘ GRUB_BUTTON_CMOS_ADDRESS’ Variants of the corresponding variables without the ‘ _BUTTON’ suffix, used to support vendor-specific power buttons. ‘ GRUB_DISTRIBUTOR’ Set by distributors of GRUB to their identifying name. This is used to generate more informative menu entry titles. ‘ GRUB_TERMINAL_INPUT’ Select the terminal input device.

You may select multiple devices here, separated by spaces. Valid terminal input names depend on the platform, but may include ‘ console’ (native platform console), ‘ serial’ (serial terminal), ‘ serial_’ (serial terminal with explicit port selection), ‘ at_keyboard’ (PC AT keyboard), or ‘ usb_keyboard’ (USB keyboard using the HID Boot Protocol, for cases where the firmware does not handle this). The default is to use the platform’s native terminal input. ‘ GRUB_TERMINAL_OUTPUT’ Select the terminal output device.

You may select multiple devices here, separated by spaces. Valid terminal output names depend on the platform, but may include ‘ console’ (native platform console), ‘ serial’ (serial terminal), ‘ serial_’ (serial terminal with explicit port selection), ‘ gfxterm’ (graphics-mode output), ‘ vga_text’ (VGA text output), ‘ mda_text’ (MDA text output), ‘ morse’ (Morse-coding using system beeper) or ‘ spkmodem’ (simple data protocol using system speaker). ‘ spkmodem’ is useful when no serial port is available. Connect the output of sending system (where GRUB is running) to line-in of receiving system (usually developer machine). On receiving system compile ‘ spkmodem-recv’ from ‘ util/spkmodem-recv.c’ and run. Parecord --channels=1 --rate=48000 --format=s16le ./spkmodem-recv The default is to use the platform’s native terminal output. ‘ GRUB_TERMINAL’ If this option is set, it overrides both ‘ GRUB_TERMINAL_INPUT’ and ‘ GRUB_TERMINAL_OUTPUT’ to the same value.

‘ GRUB_SERIAL_COMMAND’ A command to configure the serial port when using the serial console. Defaults to ‘ serial’. ‘ GRUB_CMDLINE_LINUX’ Command-line arguments to add to menu entries for the Linux kernel. ‘ GRUB_CMDLINE_LINUX_DEFAULT’ Unless ‘ GRUB_DISABLE_RECOVERY’ is set to ‘ true’, two menu entries will be generated for each Linux kernel: one default entry and one entry for recovery mode. This option lists command-line arguments to add only to the default menu entry, after those listed in ‘ GRUB_CMDLINE_LINUX’.

‘ GRUB_CMDLINE_NETBSD’ ‘ GRUB_CMDLINE_NETBSD_DEFAULT’ As ‘ GRUB_CMDLINE_LINUX’ and ‘ GRUB_CMDLINE_LINUX_DEFAULT’, but for NetBSD. ‘ GRUB_CMDLINE_GNUMACH’ As ‘ GRUB_CMDLINE_LINUX’, but for GNU Mach. ‘ GRUB_CMDLINE_XEN’ ‘ GRUB_CMDLINE_XEN_DEFAULT’ The values of these options are passed to Xen hypervisor Xen menu entries, for all respectively normal entries.

‘ GRUB_CMDLINE_LINUX_XEN_REPLACE’ ‘ GRUB_CMDLINE_LINUX_XEN_REPLACE_DEFAULT’ The values of these options replace the values of ‘ GRUB_CMDLINE_LINUX’ and ‘ GRUB_CMDLINE_LINUX_DEFAULT’ for Linux and Xen menu entries. ‘ GRUB_DISABLE_LINUX_UUID’ Normally, grub-mkconfig will generate menu entries that use universally-unique identifiers (UUIDs) to identify the root filesystem to the Linux kernel, using a ‘ root=UUID=.’ kernel parameter. This is usually more reliable, but in some cases it may not be appropriate. To disable the use of UUIDs, set this option to ‘ true’. ‘ GRUB_DISABLE_RECOVERY’ If this option is set to ‘ true’, disable the generation of recovery mode menu entries.

‘ GRUB_VIDEO_BACKEND’ If graphical video support is required, either because the ‘ gfxterm’ graphical terminal is in use or because ‘ GRUB_GFXPAYLOAD_LINUX’ is set, then grub-mkconfig will normally load all available GRUB video drivers and use the one most appropriate for your hardware. If you need to override this for some reason, then you can set this option. After grub-install has been run, the available video drivers are listed in /boot/grub/video.lst. ‘ GRUB_GFXMODE’ Set the resolution used on the ‘ gfxterm’ graphical terminal.

Note that you can only use modes which your graphics card supports via VESA BIOS Extensions (VBE), so for example native LCD panel resolutions may not be available. The default is ‘ auto’, which tries to select a preferred resolution. ‘ GRUB_BACKGROUND’ Set a background image for use with the ‘ gfxterm’ graphical terminal. The value of this option must be a file readable by GRUB at boot time, and it must end with.png,.tga,.jpg, or.jpeg. The image will be scaled if necessary to fit the screen.

‘ GRUB_THEME’ Set a theme for use with the ‘ gfxterm’ graphical terminal. ‘ GRUB_GFXPAYLOAD_LINUX’ Set to ‘ text’ to force the Linux kernel to boot in normal text mode, ‘ keep’ to preserve the graphics mode set using ‘ GRUB_GFXMODE’, ‘ widthx height’[‘ x depth’] to set a particular graphics mode, or a sequence of these separated by commas or semicolons to try several modes in sequence. Depending on your kernel, your distribution, your graphics card, and the phase of the moon, note that using this option may cause GNU/Linux to suffer from various display problems, particularly during the early part of the boot sequence. If you have problems, set this option to ‘ text’ and GRUB will tell Linux to boot in normal text mode.

‘ GRUB_DISABLE_OS_PROBER’ Normally, grub-mkconfig will try to use the external os-prober program, if installed, to discover other operating systems installed on the same system and generate appropriate menu entries for them. Set this option to ‘ true’ to disable this.

‘ GRUB_OS_PROBER_SKIP_LIST’ List of space-separated FS UUIDs of filesystems to be ignored from os-prober output. For efi chainloaders it’s @ ‘ GRUB_DISABLE_SUBMENU’ Normally, grub-mkconfig will generate top level menu entry for the kernel with highest version number and put all other found kernels or alternative menu entries for recovery mode in submenu. For entries returned by os-prober first entry will be put on top level and all others in submenu. If this option is set to ‘ y’, flat menu with all entries on top level will be generated instead.

Changing this option will require changing existing values of ‘ GRUB_DEFAULT’, ‘ fallback’ (see ) and ‘ default’ (see ) environment variables as well as saved default entry using grub-set-default and value used with grub-reboot. ‘ GRUB_ENABLE_CRYPTODISK’ If set to ‘ y’, grub-mkconfig and grub-install will check for encrypted disks and generate additional commands needed to access them during boot. Note that in this case unattended boot is not possible because GRUB will wait for passphrase to unlock encrypted container. ‘ GRUB_INIT_TUNE’ Play a tune on the speaker when GRUB starts. This is particularly useful for users unable to see the screen.

The value of this option is passed directly to. ‘ GRUB_BADRAM’ If this option is set, GRUB will issue a command to filter out specified regions of RAM.

‘ GRUB_PRELOAD_MODULES’ This option may be set to a list of GRUB module names separated by spaces. Each module will be loaded as early as possible, at the start of grub.cfg. The following options are still accepted for compatibility with existing configurations, but have better replacements: ‘ GRUB_HIDDEN_TIMEOUT’ Wait this many seconds before displaying the menu. If ESC is pressed during that time, display the menu and wait for input according to ‘ GRUB_TIMEOUT’. If a hotkey associated with a menu entry is pressed, boot the associated menu entry immediately. If the timeout expires before either of these happens, display the menu for the number of seconds specified in ‘ GRUB_TIMEOUT’ before booting the default entry. If you set ‘ GRUB_HIDDEN_TIMEOUT’, you should also set ‘ GRUB_TIMEOUT=0’ so that the menu is not displayed at all unless ESC is pressed.

This option is unset by default, and is deprecated in favour of the less confusing ‘ GRUB_TIMEOUT_STYLE=countdown’ or ‘ GRUB_TIMEOUT_STYLE=hidden’. ‘ GRUB_HIDDEN_TIMEOUT_QUIET’ In conjunction with ‘ GRUB_HIDDEN_TIMEOUT’, set this to ‘ true’ to suppress the verbose countdown while waiting for a key to be pressed before displaying the menu. This option is unset by default, and is deprecated in favour of the less confusing ‘ GRUB_TIMEOUT_STYLE=countdown’. ‘ GRUB_HIDDEN_TIMEOUT_BUTTON’ Variant of ‘ GRUB_HIDDEN_TIMEOUT’, used to support vendor-specific power buttons.

This option is unset by default, and is deprecated in favour of the less confusing ‘ GRUB_TIMEOUT_STYLE=countdown’ or ‘ GRUB_TIMEOUT_STYLE=hidden’. For more detailed customisation of grub-mkconfig’s output, you may edit the scripts in /etc/grub.d directly.

/etc/grub.d/40_custom is particularly useful for adding entire custom menu entries; simply type the menu entries you want to add at the end of that file, making sure to leave at least the first two lines intact. Next:, Previous:, Up: [][] 6.3 Multi-boot manual config Currently autogenerating config files for multi-boot environments depends on os-prober and has several shortcomings. While fixing it is scheduled for the next release, meanwhile you can make use of the power of GRUB syntax and do it yourself. A possible configuration is detailed here, feel free to adjust to your needs. First create a separate GRUB partition, big enough to hold GRUB. Some of the following entries show how to load OS installer images from this same partition, for that you obviously need to make the partition large enough to hold those images as well.

Mount this partition on/mnt/boot and disable GRUB in all OSes and manually install self-compiled latest GRUB with: grub-install --boot-directory=/mnt/boot /dev/sda In all the OSes install GRUB tools but disable installing GRUB in bootsector, so you’ll have menu.lst and grub.cfg available for use. Also disable os-prober use by setting: GRUB_DISABLE_OS_PROBER=true in /etc/default/grub Then write a grub.cfg (/mnt/boot/grub/grub.cfg). Previous:, Up: [][] 6.4 Embedding a configuration file into GRUB GRUB supports embedding a configuration file directly into the core image, so that it is loaded before entering normal mode. This is useful, for example, when it is not straightforward to find the real configuration file, or when you need to debug problems with loading that file. Grub-install uses this feature when it is not using BIOS disk functions or when installing to a different disk from the one containing /boot/grub, in which case it needs to use the search command (see ) to find /boot/grub. To embed a configuration file, use the -c option to grub-mkimage.

The file is copied into the core image, so it may reside anywhere on the file system, and may be removed after running grub-mkimage. After the embedded configuration file (if any) is executed, GRUB will load the ‘ normal’ module (see ), which will then read the real configuration file from $prefix/grub.cfg. By this point, the root variable will also have been set to the root device name.

For example, prefix might be set to ‘ (hd0,1)/boot/grub’, and root might be set to ‘ hd0,1’. Thus, in most cases, the embedded configuration file only needs to set the prefix and root variables, and then drop through to GRUB’s normal processing.

A typical example of this might look like this. Search.fs_uuid 01234567-89ab-cdef-0123-456789abcdef root set prefix=($root)/boot/grub (The ‘ search_fs_uuid’ module must be included in the core image for this example to work.) In more complex cases, it may be useful to read other configuration files directly from the embedded configuration file. This allows such things as reading files not called grub.cfg, or reading files from a directory other than that where GRUB’s loadable modules are installed. To do this, include the ‘ configfile’ and ‘ normal’ modules in the core image, and embed a configuration file that uses the configfile command to load another file. The following example of this also requires the echo, search_label, and test modules to be included in the core image. Next:, Previous:, Up: [][] 7 Theme file format 7.1 Introduction The GRUB graphical menu supports themes that can customize the layout and appearance of the GRUB boot menu. The theme is configured through a plain text file that specifies the layout of the various GUI components (including the boot menu, timeout progress bar, and text messages) as well as the appearance using colors, fonts, and images.

Example is available in docs/example_theme.txt 7.2 Theme Elements 7.2.1 Colors Colors can be specified in several ways: • HTML-style “#RRGGBB” or “#RGB” format, where *R*, *G*, and *B* are hexadecimal digits (e.g., “#8899FF”) • as comma-separated decimal RGB values (e.g., “128, 128, 255”) • with “SVG 1.0 color names” (e.g., “cornflowerblue”) which must be specified in lowercase. 7.2.2 Fonts The fonts GRUB uses “PFF2 font format” bitmap fonts. Fonts are specified with full font names. Currently there is no provision for a preference list of fonts, or deriving one font from another. Fonts are loaded with the “loadfont” command in GRUB (). To see the list of loaded fonts, execute the “lsfonts” command ().

If there are too many fonts to fit on screen, do “set pager=1” before executing “lsfonts”. 7.2.3 Progress Bar. Figure 7.2 Progress bars are used to display the remaining time before GRUB boots the default menu entry.

To create a progress bar that will display the remaining time before automatic boot, simply create a “progress_bar” component with the id “__timeout__”. This indicates to GRUB that the progress bar should be updated as time passes, and it should be made invisible if the countdown to automatic boot is interrupted by the user. Progress bars may optionally have text displayed on them. This text is controlled by variable “text” which contains a printf template with the only argument%d is the number of seconds remaining. Additionally special values “@TIMEOUT_NOTIFICATION_SHORT@”, “@TIMEOUT_NOTIFICATION_MIDDLE@”, “@TIMEOUT_NOTIFICATION_LONG@” are replaced with standard and translated templates. 7.2.4 Circular Progress Indicator The circular progress indicator functions similarly to the progress bar. When given an id of “__timeout__”, GRUB updates the circular progress indicator’s value to indicate the time remaining.

For the circular progress indicator, there are two images used to render it: the *center* image, and the *tick* image. The center image is rendered in the center of the component, while the tick image is used to render each mark along the circumference of the indicator. 7.2.5 Labels Text labels can be placed on the boot screen. The font, color, and horizontal alignment can be specified for labels. If a label is given the id “__timeout__”, then the “text” property for that label is also updated with a message informing the user of the number of seconds remaining until automatic boot. This is useful in case you want the text displayed somewhere else instead of directly on the progress bar.

7.2.6 Boot Menu The boot menu where GRUB displays the menu entries from the “grub.cfg” file. It is a list of items, where each item has a title and an optional icon. The icon is selected based on the *classes* specified for the menu entry. If there is a PNG file named “myclass.png” in the “grub/themes/icons” directory, it will be displayed for items which have the class *myclass*.

The boot menu can be customized in several ways, such as the font and color used for the menu entry title, and by specifying styled boxes for the menu itself and for the selected item highlight. 7.2.7 Styled Boxes One of the most important features for customizing the layout is the use of *styled boxes*. A styled box is composed of 9 rectangular (and potentially empty) regions, which are used to seamlessly draw the styled box on screen: Northwest (nw) North (n) Northeast (ne) West (w) Center (c) East (e) Southwest (sw) South (s) Southeast (se) To support any size of box on screen, the center slice and the slices for the top, bottom, and sides are all scaled to the correct size for the component on screen, using the following rules: • The edge slices (north, south, east, and west) are scaled in the direction of the edge they are adjacent to.

For instance, the west slice is scaled vertically. • The corner slices (northwest, northeast, southeast, and southwest) are not scaled. • The center slice is scaled to fill the remaining space in the middle. As an example of how an image might be sliced up, consider the styled box used for a terminal view.

Next:, Previous:, Up: [][] 9 Using GRUB via a serial line This chapter describes how to use the serial terminal support in GRUB. If you have many computers or computers with no display/keyboard, it could be very useful to control the computers through serial communications. To connect one computer with another via a serial line, you need to prepare a null-modem (cross) serial cable, and you may need to have multiport serial boards, if your computer doesn’t have extra serial ports. In addition, a terminal emulator is also required, such as minicom. Refer to a manual of your operating system, for more information. As for GRUB, the instruction to set up a serial terminal is quite simple.

Here is an example. Grub>serial --unit=0 --speed=9600 grub>terminal_input serial; terminal_output serial The command serial initializes the serial unit 0 with the speed 9600bps. The serial unit 0 is usually called ‘ COM1’, so, if you want to use COM2, you must specify ‘ --unit=1’ instead.

This command accepts many other options, so please refer to, for more details. The commands terminal_input (see ) and terminal_output (see ) choose which type of terminal you want to use. In the case above, the terminal will be a serial terminal, but you can also pass console to the command, as ‘ terminal_input serial console’. Hey Say Jump Concert Download on this page. In this case, a terminal in which you press any key will be selected as a GRUB terminal. In the example above, note that you need to put both commands on the same command line, as you will lose the ability to type commands on the console after the first command. However, note that GRUB assumes that your terminal emulator is compatible with VT100 by default.

This is true for most terminal emulators nowadays, but you should pass the option --dumb to the command if your terminal emulator is not VT100-compatible or implements few VT100 escape sequences. If you specify this option then GRUB provides you with an alternative menu interface, because the normal menu requires several fancy features of your terminal. Next:, Previous:, Up: [][] 10 Using GRUB with vendor power-on keys Some laptop vendors provide an additional power-on button which boots another OS. GRUB supports such buttons with the ‘ GRUB_TIMEOUT_BUTTON’, ‘ GRUB_TIMEOUT_STYLE_BUTTON’, ‘ GRUB_DEFAULT_BUTTON’, and ‘ GRUB_BUTTON_CMOS_ADDRESS’ variables in default/grub (see ). ‘ GRUB_TIMEOUT_BUTTON’, ‘ GRUB_TIMEOUT_STYLE_BUTTON’, and ‘ GRUB_DEFAULT_BUTTON’ are used instead of the corresponding variables without the ‘ _BUTTON’ suffix when powered on using the special button. ‘ GRUB_BUTTON_CMOS_ADDRESS’ is vendor-specific and partially model-specific.

Values known to the GRUB team are: Dell XPS M1330M 121:3 Dell XPS M1530 85:3 Dell Latitude E4300 85:3 Asus EeePC 1005PE 84:1 (unconfirmed) LENOVO ThinkPad T410s (2912W1C) 101:3 To take full advantage of this function, install GRUB into the MBR (see ). If you have a laptop which has a similar feature and not in the above list could you figure your address and contribute? To discover the address do the following: • boot normally •. Next:, Previous:, Up: [][] 11 GRUB image files GRUB consists of several images: a variety of bootstrap images for starting GRUB in various ways, a kernel image, and a set of modules which are combined with the kernel image to form a core image. Here is a short overview of them. Boot.img On PC BIOS systems, this image is the first part of GRUB to start. It is written to a master boot record (MBR) or to the boot sector of a partition.

Because a PC boot sector is 512 bytes, the size of this image is exactly 512 bytes. The sole function of boot.img is to read the first sector of the core image from a local disk and jump to it. Because of the size restriction, boot.img cannot understand any file system structure, so grub-install hardcodes the location of the first sector of the core image into boot.img when installing GRUB. Diskboot.img This image is used as the first sector of the core image when booting from a hard disk.

It reads the rest of the core image into memory and starts the kernel. Since file system handling is not yet available, it encodes the location of the core image using a block list format.

Cdboot.img This image is used as the first sector of the core image when booting from a CD-ROM drive. It performs a similar function to diskboot.img. Pxeboot.img This image is used as the start of the core image when booting from the network using PXE. Lnxboot.img This image may be placed at the start of the core image in order to make GRUB look enough like a Linux kernel that it can be booted by LILO using an ‘ image=’ section. Kernel.img This image contains GRUB’s basic run-time facilities: frameworks for device and file handling, environment variables, the rescue mode command-line parser, and so on. It is rarely used directly, but is built into all core images.

Core.img This is the core image of GRUB. It is built dynamically from the kernel image and an arbitrary list of modules by the grub-mkimage program. Usually, it contains enough modules to access /boot/grub, and loads everything else (including menu handling, the ability to load target operating systems, and so on) from the file system at run-time.

The modular design allows the core image to be kept small, since the areas of disk where it must be installed are often as small as 32KB. See, for details on where the core image can be installed on PC systems. *.mod Everything else in GRUB resides in dynamically loadable modules. These are often loaded automatically, or built into the core image if they are essential, but may also be loaded manually using the insmod command (see ). For GRUB Legacy users GRUB 2 has a different design from GRUB Legacy, and so correspondences with the images it used cannot be exact.

Nevertheless, GRUB Legacy users often ask questions in the terms they are familiar with, and so here is a brief guide to how GRUB 2’s images relate to that. Stage1 Stage 1 from GRUB Legacy was very similar to boot.img in GRUB 2, and they serve the same function.

*_stage1_5 In GRUB Legacy, Stage 1.5’s function was to include enough filesystem code to allow the much larger Stage 2 to be read from an ordinary filesystem. In this respect, its function was similar to core.img in GRUB 2. Blood Guts And Glory Flames Of War Pdf Download. However, core.img is much more capable than Stage 1.5 was; since it offers a rescue shell, it is sometimes possible to recover manually in the event that it is unable to load any other modules, for example if partition numbers have changed. Core.img is built in a more flexible way, allowing GRUB 2 to support reading modules from advanced disk types such as LVM and RAID.

GRUB Legacy could run with only Stage 1 and Stage 2 in some limited configurations, while GRUB 2 requires core.img and cannot work without it. Stage2 GRUB 2 has no single Stage 2 image. Instead, it loads modules from /boot/grub at run-time. Stage2_eltorito In GRUB 2, images for booting from CD-ROM drives are now constructed using cdboot.img and core.img, making sure that the core image contains the ‘ iso9660’ module. It is usually best to use the grub-mkrescue program for this.

Nbgrub There is as yet no equivalent for nbgrub in GRUB 2; it was used by Etherboot and some other network boot loaders. Pxegrub In GRUB 2, images for PXE network booting are now constructed using pxeboot.img and core.img, making sure that the core image contains the ‘ pxe’ and ‘ pxecmd’ modules. Next:, Previous:, Up: [][] 12 Core image size limitation Heavily limited platforms: • i386-pc (normal and PXE): the core image size (compressed) is limited by 458240 bytes. Kernel.img (.text +.data +.bss, uncompressed) is limited by 392704 bytes.

Module size (uncompressed) + kernel.img (.text +.data, uncompressed) is limited by the size of contiguous chunk at 1M address. • sparc64-ieee1275: kernel.img (.text +.data +.bss) + modules + 256K (stack) + 2M (heap) is limited by space available at 0x4400. On most platforms it’s just 3 or 4M since ieee1275 maps only so much. • i386-ieee1275: kernel.img (.text +.data +.bss) + modules is limited by memory available at 0x10000, at most 596K Lightly limited platforms: • *-xen: limited only by adress space and RAM size. • i386-qemu: kernel.img (.text +.data +.bss) is limited by 392704 bytes.

(core.img would be limited by ROM size but it’s unlimited on qemu • All EFI platforms: limited by contiguous RAM size and possibly firmware bugs • Coreboot and multiboot. Kernel.img (.text +.data +.bss) is limited by 392704 bytes. Module size is limited by the size of contiguous chunk at 1M address.

( device[, partmap-name1 part-num1[, partmap-name2 part-num2[.]]]) ‘ []’ means the parameter is optional. Device depends on the disk driver in use. BIOS and EFI disks use either ‘ fd’ or ‘ hd’ followed by a digit, like ‘ fd0’, or ‘ cd’. AHCI, PATA (ata), crypto, USB use the name of driver followed by a number. Memdisk and host are limited to one disk and so it’s refered just by driver name. RAID (md), ofdisk (ieee1275 and nand), LVM (lvm), LDM, virtio (vdsk) and arcdisk (arc) use intrinsic name of disk prefixed by driver name.

Additionally just “nand” refers to the disk aliased as “nand”. Conflicts are solved by suffixing a number if necessarry. Commas need to be escaped.

Loopback uses whatever name specified to loopback command. Hostdisk uses names specified in device.map as long as it’s of the form [fhc]d[0-9]* or hostdisk/. For crypto and RAID (md) additionally you can use the syntax uuid/. For LVM additionally you can use the syntax lvmid//. (fd0) (hd0) (cd) (ahci0) (ata0) (crypto0) (usb0) (cryptouuid/123456789abcdefabcdef0) (mduuid/123456789abcdefabcdef0) (lvm/system-root) (lvmid/F1ikgD-2RES-306G-il9M-7iwa-4NKW-EbV1NV/eLGuCQ-L4Ka-XUgR-sjtJ-ffch-bajr-fCNfz5) (md/myraid) (md/0) (ieee1275/disk2) (ieee1275//pci@1f,0/ide@d/disk@2) (nand) (memdisk) (host) (myloop) (hostdisk//dev/sda) part-num represents the partition number of device, starting from one. Partname is optional but is recommended since disk may have several top-level partmaps.

Specifying third and later component you can access to subpartitions. The syntax ‘ (hd0)’ represents using the entire disk (or the MBR when installing GRUB), while the syntax ‘ (hd0,1)’ represents using the first partition of the disk (or the boot sector of the partition when installing GRUB).

Next:, Previous:, Up: [][] 13.2 How to specify files There are two ways to specify files, by absolute file name and by block list. An absolute file name resembles a Unix absolute file name, using ‘ /’ for the directory separator (not ‘ ’ as in DOS). One example is ‘ (hd0,1)/boot/grub/grub.cfg’. This means the file /boot/grub/grub.cfg in the first partition of the first hard disk.

If you omit the device name in an absolute file name, GRUB uses GRUB’s root device implicitly. So if you set the root device to, say, ‘ (hd1,1)’ by the command ‘ set root=(hd1,1)’ (see ), then /boot/kernel is the same as (hd1,1)/boot/kernel.

On ZFS filesystem the first path component must be volume‘ @’[ snapshot]. So ‘ /rootvol@snap-129/boot/grub/grub.cfg’ refers to file ‘ /boot/grub/grub.cfg’ in snapshot of volume ‘ rootvol’ with name ‘ snap-129’. Trailing ‘ @’ after volume name is mandatory even if snapshot name is omitted. Next:, Previous:, Up: [][] 14 GRUB’s user interface GRUB has both a simple menu interface for choosing preset entries from a configuration file, and a highly flexible command-line for performing any desired combination of boot commands. GRUB looks for its configuration file as soon as it is loaded.

If one is found, then the full menu interface is activated using whatever entries were found in the file. If you choose the command-line menu option, or if the configuration file was not found, then GRUB drops to the command-line interface.

•: The flexible command-line interface •: The simple menu interface •: Editing a menu entry. Next:, Up: [][] 14.1 The flexible command-line interface The command-line interface provides a prompt and after it an editable text area much like a command-line in Unix or DOS. Each command is immediately executed after it is entered.

The commands (see ) are a subset of those available in the configuration file, used with exactly the same syntax. Cursor movement and editing of the text on the line can be done via a subset of the functions available in the Bash shell: C-f PC right key Move forward one character. C-b PC left key Move back one character. C-a HOME Move to the start of the line.

C-e END Move the the end of the line. C-d DEL Delete the character underneath the cursor. C-h BS Delete the character to the left of the cursor. C-k Kill the text from the current cursor position to the end of the line. C-u Kill backward from the cursor to the beginning of the line.

C-y Yank the killed text back into the buffer at the cursor. C-p PC up key Move up through the history list. C-n PC down key Move down through the history list. When typing commands interactively, if the cursor is within or before the first word in the command-line, pressing the TAB key (or C-i) will display a listing of the available commands, and if the cursor is after the first word, the TAB will provide a completion listing of disks, partitions, and file names depending on the context. Note that to obtain a list of drives, one must open a parenthesis, as root (. Note that you cannot use the completion functionality in the TFTP filesystem. This is because TFTP doesn’t support file name listing for the security.

Next:, Previous:, Up: [][] 14.2 The simple menu interface The menu interface is quite easy to use. Its commands are both reasonably intuitive and described on screen. Basically, the menu interface provides a list of boot entries to the user to choose from. Use the arrow keys to select the entry of choice, then press RET to run it. An optional timeout is available to boot the default entry (the first one if not set), which is aborted by pressing any key. Commands are available to enter a bare command-line by pressing c (which operates exactly like the non-config-file version of GRUB, but allows one to return to the menu if desired by pressing ESC) or to edit any of the boot entries by pressing e.

If you protect the menu interface with a password (see ), all you can do is choose an entry by pressing RET, or press p to enter the password. Previous:, Up: [][] 14.3 Editing a menu entry The menu entry editor looks much like the main menu interface, but the lines in the menu are individual commands in the selected entry instead of entry names. If an ESC is pressed in the editor, it aborts all the changes made to the configuration entry and returns to the main menu interface. Each line in the menu entry can be edited freely, and you can add new lines by pressing RET at the end of a line. To boot the edited entry, press Ctrl-x.

Although GRUB unfortunately does not support undo, you can do almost the same thing by just returning to the main menu using ESC. Next:, Previous:, Up: [][] 15 GRUB environment variables GRUB supports environment variables which are rather like those offered by all Unix-like systems. Environment variables have a name, which is unique and is usually a short identifier, and a value, which is an arbitrary string of characters. They may be set (see ), unset (see ), or looked up (see ) by name. A number of environment variables have special meanings to various parts of GRUB.

Others may be used freely in GRUB configuration files. Next:, Previous:, Up: [][] 15.1.6 color_normal This variable contains the “normal” foreground and background terminal colors, separated by a slash (‘ /’). Setting this variable changes those colors. Each color must be a name from the following list: • black • blue • green • cyan • red • magenta • brown • light-gray • dark-gray • light-blue • light-green • light-cyan • light-red • light-magenta • yellow • white The default is ‘ light-gray/black’.

The color support support varies from terminal to terminal. ‘ morse’ has no color support at all. ‘ mda_text’ color support is limited to highlighting by black/white reversal.

‘ console’ on ARC, EMU and IEEE1275, ‘ serial_*’ and ‘ spkmodem’ are governed by terminfo and support only 8 colors if in modes ‘ vt100-color’ (default for console on emu), ‘ arc’ (default for console on ARC), ‘ ieee1275’ (default for console on IEEE1275). When in mode ‘ vt100’ then the color support is limited to highlighting by black/white reversal. When in mode ‘ dumb’ there is no color support.

When console supports no colors this setting is ignored. When console supports 8 colors, then the colors from the second half of the previous list are mapped to the matching colors of first half.

‘ console’ on EFI and BIOS and ‘ vga_text’ support all 16 colors. ‘ gfxterm’ supports all 16 colors and would be theoretically extendable to support whole rgb24 palette but currently there is no compelling reason to go beyond the current 16 colors. Next:, Previous:, Up: [][] 15.1.12 gfxmode If this variable is set, it sets the resolution used on the ‘ gfxterm’ graphical terminal. Note that you can only use modes which your graphics card supports via VESA BIOS Extensions (VBE), so for example native LCD panel resolutions may not be available. The default is ‘ auto’, which selects a platform-specific default that should look reasonable.

Supported modes can be listed by ‘ videoinfo’ command in GRUB. The resolution may be specified as a sequence of one or more modes, separated by commas (‘,’) or semicolons (‘;’); each will be tried in turn until one is found. Each mode should be either ‘ auto’, ‘ widthx height’, or ‘ widthx heightx depth’. Next:, Previous:, Up: [][] 15.1.13 gfxpayload If this variable is set, it controls the video mode in which the Linux kernel starts up, replacing the ‘ vga=’ boot option (see ). It may be set to ‘ text’ to force the Linux kernel to boot in normal text mode, ‘ keep’ to preserve the graphics mode set using ‘ gfxmode’, or any of the permitted values for ‘ gfxmode’ to set a particular graphics mode (see ). Depending on your kernel, your distribution, your graphics card, and the phase of the moon, note that using this option may cause GNU/Linux to suffer from various display problems, particularly during the early part of the boot sequence.

If you have problems, set this variable to ‘ text’ and GRUB will tell Linux to boot in normal text mode. The default is platform-specific. On platforms with a native text mode (such as PC BIOS platforms), the default is ‘ text’. Otherwise the default may be ‘ auto’ or a specific video mode. This variable is often set by ‘ GRUB_GFXPAYLOAD_LINUX’ (see ). Previous:, Up: [][] 15.2 The GRUB environment block It is often useful to be able to remember a small amount of information from one boot to the next.

For example, you might want to set the default menu entry based on what was selected the last time. GRUB deliberately does not implement support for writing files in order to minimise the possibility of the boot loader being responsible for file system corruption, so a GRUB configuration file cannot just create a file in the ordinary way. However, GRUB provides an “environment block” which can be used to save a small amount of state. The environment block is a preallocated 1024-byte file, which normally lives in /boot/grub/grubenv (although you should not assume this). At boot time, the load_env command (see ) loads environment variables from it, and the save_env (see ) command saves environment variables to it. From a running system, the grub-editenv utility can be used to edit the environment block.

For safety reasons, this storage is only available when installed on a plain disk (no LVM or RAID), using a non-checksumming filesystem (no ZFS), and using BIOS or EFI functions (no ATA, USB or IEEE1275). Grub-mkconfig uses this facility to implement ‘ GRUB_SAVEDEFAULT’ (see ).

Next:, Previous:, Up: [][] 16 The list of available commands In this chapter, we list all commands that are available in GRUB. Commands belong to different groups. A few can only be used in the global section of the configuration file (or “menu”); most of them can be entered on the command-line and can be used either anywhere in the menu or specifically in the menu entries. In rescue mode, only the insmod (see ), ls (see ), set (see ), and unset (see ) commands are normally available. If you end up in rescue mode and do not know what to do, then see.

Next:, Up: [][] 16.1 The list of commands for the menu only The semantics used in parsing the configuration file are the following: • The files must be in plain-text format. • ‘ #’ at the beginning of a line in a configuration file means it is only a comment. • Options are separated by spaces. • All numbers can be either decimal or hexadecimal.

A hexadecimal number must be preceded by ‘ 0x’, and is case-insensitive. These commands can only be used in the menu: •: Start a menu entry •: Group menu entries. Next:, Up: [][] 16.2.1 serial Command: serial [ --unit=unit] [ --port=port] [ --speed=speed] [ --word=word] [ --parity=parity] [ --stop=stop] Initialize a serial device. Unit is a number in the range 0-3 specifying which serial port to use; default is 0, which corresponds to the port often called COM1.

Port is the I/O port where the UART is to be found; if specified it takes precedence over unit. Speed is the transmission speed; default is 9600. Word and stop are the number of data bits and stop bits. Data bits must be in the range 5-8 and stop bits must be 1 or 2. Default is 8 data bits and one stop bit.

Parity is one of ‘ no’, ‘ odd’, ‘ even’ and defaults to ‘ no’. The serial port is not used as a communication channel unless the terminal_input or terminal_output command is used (see, see ).

Next:, Previous:, Up: [][] 16.2.2 terminal_input Command: terminal_input [ --append --remove] [terminal1] [terminal2] List or select an input terminal. With no arguments, list the active and available input terminals.

With --append, add the named terminals to the list of active input terminals; any of these may be used to provide input to GRUB. With --remove, remove the named terminals from the active list. With no options but a list of terminal names, make only the listed terminal names active. Next:, Previous:, Up: [][] 16.2.3 terminal_output Command: terminal_output [ --append --remove] [terminal1] [terminal2] List or select an output terminal. With no arguments, list the active and available output terminals. With --append, add the named terminals to the list of active output terminals; all of these will receive output from GRUB.

With --remove, remove the named terminals from the active list. With no options but a list of terminal names, make only the listed terminal names active. Previous:, Up: [][] 16.2.4 terminfo Command: terminfo [-a -u -v] [term] Define the capabilities of your terminal by giving the name of an entry in the terminfo database, which should correspond roughly to a ‘ TERM’ environment variable in Unix.

The currently available terminal types are ‘ vt100’, ‘ vt100-color’, ‘ ieee1275’, and ‘ dumb’. If you need other terminal types, please contact us to discuss the best way to include support for these in GRUB. The -a ( --ascii), -u ( --utf8), and -v ( --visual-utf8) options control how non-ASCII text is displayed.

-a specifies an ASCII-only terminal; -u specifies logically-ordered UTF-8; and -v specifies 'visually-ordered UTF-8' (in other words, arranged such that a terminal emulator without bidirectional text support will display right-to-left text in the proper order; this is not really proper UTF-8, but a workaround). If no option or terminal type is specified, the current terminal type is printed. Next:, Previous:, Up: [][] 16.3 The list of command-line and menu entry commands These commands are usable in the command-line and in menu entries. If you forget a command, you can run the command help (see ). Next:, Previous:, Up: [][] 16.3.2 acpi Command: acpi [ -1 -2] [ --exclude=table1, --load-only=table1,] [ --oemid=id] [ --oemtable=table] [ --oemtablerev=rev] [ --oemtablecreator=creator] [ --oemtablecreatorrev=rev] [ --no-ebda] filename Modern BIOS systems normally implement the Advanced Configuration and Power Interface (ACPI), and define various tables that describe the interface between an ACPI-compliant operating system and the firmware.

In some cases, the tables provided by default only work well with certain operating systems, and it may be necessary to replace some of them. Normally, this command will replace the Root System Description Pointer (RSDP) in the Extended BIOS Data Area to point to the new tables. If the --no-ebda option is used, the new tables will be known only to GRUB, but may be used by GRUB’s EFI emulation. Next:, Previous:, Up: [][] 16.3.6 badram Command: badram addr,mask[,addr,mask.] Filter out bad RAM. This command notifies the memory manager that specified regions of RAM ought to be filtered out (usually, because they’re damaged). This remains in effect after a payload kernel has been loaded by GRUB, as long as the loaded kernel obtains its memory map from GRUB.

Kernels that support this include Linux, GNU Mach, the kernel of FreeBSD and Multiboot kernels in general. Syntax is the same as provided by the: a list of address/mask pairs.

Given a page-aligned address and a base address / mask pair, if all the bits of the page-aligned address that are enabled by the mask match with the base address, it means this page is to be filtered. This syntax makes it easy to represent patterns that are often result of memory damage, due to physical distribution of memory cells.

Next:, Previous:, Up: [][] 16.3.19 cryptomount Command: cryptomount device -u uuid -a -b Setup access to encrypted device. If necessary, passphrase is requested interactively. Option device configures specific grub device (see ); option -u uuid configures device with specified uuid; option -a configures all detected encrypted devices; option -b configures all geli containers that have boot flag set. GRUB suports devices encrypted using LUKS and geli.

Note that necessary modules ( luks and geli) have to be loaded manually before this command can be used. Next:, Previous:, Up: [][] 16.3.22 distrust Command: distrust pubkey_id Remove public key pubkey_id from GRUB’s keyring of trusted keys. Pubkey_id is the last four bytes (eight hexadecimal digits) of the GPG v4 key id, which is also the output of list_trusted (see ). Outside of GRUB, the key id can be obtained using gpg --fingerprint).

These keys are used to validate signatures when environment variable check_signatures is set to enforce (see ), and by some invocations of verify_detached (see ). See, for more information. Next:, Previous:, Up: [][] 16.3.29 gptsync Command: gptsync device [partition[+/-[type]]] Disks using the GUID Partition Table (GPT) also have a legacy Master Boot Record (MBR) partition table for compatibility with the BIOS and with older operating systems. The legacy MBR can only represent a limited subset of GPT partition entries.

This command populates the legacy MBR with the specified partition entries on device. Up to three partitions may be used. Type is an MBR partition type code; prefix with ‘ 0x’ if you want to enter this in hexadecimal.

The separator between partition and type may be ‘ +’ to make the partition active, or ‘ -’ to make it inactive; only one partition may be active. If both the separator and type are omitted, then the partition will be inactive.

Next:, Previous:, Up: [][] 16.3.31 hashsum Command: hashsum --hash hash --keep-going --uncompress --check file [ --prefix dir] file Compute or verify file hashes. Hash type is selected with option --hash. Supported hashes are: ‘ adler32’, ‘ crc64’, ‘ crc32’, ‘ crc32rfc1510’, ‘ crc24rfc2440’, ‘ md4’, ‘ md5’, ‘ ripemd160’, ‘ sha1’, ‘ sha224’, ‘ sha256’, ‘ sha512’, ‘ sha384’, ‘ tiger192’, ‘ tiger’, ‘ tiger2’, ‘ whirlpool’. Option --uncompress uncompresses files before computing hash. When list of files is given, hash of each file is computed and printed, followed by file name, each file on a new line. When option --check is given, it points to a file that contains list of hash name pairs in the same format as used by UNIX md5sum command.

Option --prefix may be used to give directory where files are located. Hash verification stops after the first mismatch was found unless option --keep-going was given. The exit code $? Is set to 0 if hash verification is successful. If it fails, $? Is set to a nonzero value.

Next:, Previous:, Up: [][] 16.3.37 linux Command: linux file Load a Linux kernel image from file. The rest of the line is passed verbatim as the kernel command-line. Any initrd must be reloaded after using this command (see ). On x86 systems, the kernel will be booted using the 32-bit boot protocol. Note that this means that the ‘ vga=’ boot option will not work; if you want to set a special video mode, you will need to use GRUB commands such as ‘ set gfxpayload=1024x768’ or ‘ set gfxpayload=keep’ (to keep the same mode as used in GRUB) instead. GRUB can automatically detect some uses of ‘ vga=’ and translate them to appropriate settings of ‘ gfxpayload’. The linux16 command (see ) avoids this restriction.

Next:, Previous:, Up: [][] 16.3.38 linux16 Command: linux16 file Load a Linux kernel image from file in 16-bit mode. The rest of the line is passed verbatim as the kernel command-line. Any initrd must be reloaded after using this command (see ). The kernel will be booted using the traditional 16-bit boot protocol.

As well as bypassing problems with ‘ vga=’ described in, this permits booting some other programs that implement the Linux boot protocol for the sake of convenience. This command is only available on x86 systems. Next:, Previous:, Up: [][] 16.3.41 load_env Command: load_env [ --file file] [ --skip-sig] [whitelisted_variable_name] Load all variables from the environment block file into the environment. The --file option overrides the default location of the environment block. The --skip-sig option skips signature checking even when the value of environment variable check_signatures is set to enforce (see ). If one or more variable names are provided as arguments, they are interpreted as a whitelist of variables to load from the environment block file.

Variables set in the file but not present in the whitelist are ignored. The --skip-sig option should be used with care, and should always be used in concert with a whitelist of acceptable variables whose values should be set. Failure to employ a carefully constructed whitelist could result in reading a malicious value into critical environment variables from the file, such as setting check_signatures=no, modifying prefix to boot from an unexpected location or not at all, etc. When used with care, --skip-sig and the whitelist enable an administrator to configure a system to boot only signed configurations, but to allow the user to select from among multiple configurations, and to enable “one-shot” boot attempts and “savedefault” behavior.

See, for more information. Next:, Previous:, Up: [][] 16.3.49 multiboot Command: multiboot [--quirk-bad-kludge] [--quirk-modules-after-kernel] file Load a multiboot kernel image from file. The rest of the line is passed verbatim as the kernel command-line. Any module must be reloaded after using this command (see ). Some kernels have known problems. You need to specify –quirk-* for those. –quirk-bad-kludge is a problem seen in several products that they include loading kludge information with invalid data in ELF file.

GRUB prior to 0.97 and some custom builds prefered ELF information while 0.97 and GRUB 2 use kludge. Use this option to ignore kludge. Known affected systems: old Solaris, SkyOS. –quirk-modules-after-kernel is needed for kernels which load at relatively high address e.g.

16MiB mark and can’t cope with modules stuffed between 1MiB mark and beginning of the kernel. Known afftected systems: VMWare.

Next:, Previous:, Up: [][] 16.3.51 normal Command: normal [file] Enter normal mode and display the GRUB menu. In normal mode, commands, filesystem modules, and cryptography modules are automatically loaded, and the full GRUB script parser is available. Other modules may be explicitly loaded using insmod (see ).

If a file is given, then commands will be read from that file. Otherwise, they will be read from $prefix/grub.cfg if it exists.

Normal may be called from within normal mode, creating a nested environment. It is more usual to use configfile (see ) for this. Next:, Previous:, Up: [][] 16.3.53 parttool Command: parttool partition commands Make various modifications to partition table entries. Each command is either a boolean option, in which case it must be followed with ‘ +’ or ‘ -’ (with no intervening space) to enable or disable that option, or else it takes a value in the form ‘ command= value’.

Currently, parttool is only useful on DOS partition tables (also known as Master Boot Record, or MBR). On these partition tables, the following commands are available: ‘ boot’ (boolean) When enabled, this makes the selected partition be the active (bootable) partition on its disk, clearing the active flag on all other partitions. This command is limited to primary partitions. ‘ type’ (value) Change the type of an existing partition. The value must be a number in the range 0-0xFF (prefix with ‘ 0x’ to enter it in hexadecimal).

‘ hidden’ (boolean) When enabled, this hides the selected partition by setting the hidden bit in its partition type code; when disabled, unhides the selected partition by clearing this bit. This is useful only when booting DOS or Wwindows and multiple primary FAT partitions exist in one disk. Next:, Previous:, Up: [][] 16.3.56 play Command: play file tempo [pitch1 duration1] [pitch2 duration2] Plays a tune If the argument is a file name (see ), play the tune recorded in it. The file format is first the tempo as an unsigned 32bit little-endian number, then pairs of unsigned 16bit little-endian numbers for pitch and duration pairs. If the arguments are a series of numbers, play the inline tune. The tempo is the base for all note durations. 60 gives a 1-second base, 120 gives a half-second base, etc.

Pitches are Hz. Set pitch to 0 to produce a rest. Next:, Previous:, Up: [][] 16.3.63 save_env Command: save_env [ --file file] var Save the named variables from the environment to the environment block file. The --file option overrides the default location of the environment block. This command will operate successfully even when environment variable check_signatures is set to enforce (see ), since it writes to disk and does not alter the behavior of GRUB based on any contents of disk that have been read.

It is possible to modify a digitally signed environment block file from within GRUB using this command, such that its signature will no longer be valid on subsequent boots. Care should be taken in such advanced configurations to avoid rendering the system unbootable.

See, for more information. Next:, Previous:, Up: [][] 16.3.64 search Command: search [ --file --label --fs-uuid] [ --set [var]] [ --no-floppy] name Search devices by file ( -f, --file), filesystem label ( -l, --label), or filesystem UUID ( -u, --fs-uuid).

If the --set option is used, the first device found is set as the value of environment variable var. The default variable is ‘ root’. The --no-floppy option prevents searching floppy devices, which can be slow. The ‘ search.file’, ‘ search.fs_label’, and ‘ search.fs_uuid’ commands are aliases for ‘ search --file’, ‘ search --label’, and ‘ search --fs-uuid’ respectively. Next:, Previous:, Up: [][] 16.3.72 test Command: test expression Evaluate expression and return zero exit status if result is true, non zero status otherwise. Next:, Previous:, Up: [][] 16.3.74 trust Command: trust [ --skip-sig] pubkey_file Read public key from pubkey_file and add it to GRUB’s internal list of trusted public keys. These keys are used to validate digital signatures when environment variable check_signatures is set to enforce.

Note that if check_signatures is set to enforce when trust executes, then pubkey_file must itself be properly signed. The --skip-sig option can be used to disable signature-checking when reading pubkey_file itself. It is expected that --skip-sig is useful for testing and manual booting. See, for more information. Next:, Previous:, Up: [][] 16.3.77 verify_detached Command: verify_detached [ --skip-sig] file signature_file [pubkey_file] Verifies a GPG-style detached signature, where the signed file is file, and the signature itself is in file signature_file. Optionally, a specific public key to use can be specified using pubkey_file.

When environment variable check_signatures is set to enforce, then pubkey_file must itself be properly signed by an already-trusted key. An unsigned pubkey_file can be loaded by specifying --skip-sig.

If pubkey_file is omitted, then public keys from GRUB’s trusted keys (see, see, and see ) are tried. Is set to 0 if the signature validates successfully. If validation fails, it is set to a non-zero value. See, for more information. Next:, Previous:, Up: [][] 16.4.4 net_bootp Command: net_bootp [ card] Perform configuration of card using DHCP protocol.

If no card name is specified, try to configure all existing cards. If configuration was successful, interface with name card‘:dhcp’ and configured address is added to card.

Additionally the following DHCP options are recognized and processed: ‘ 1 (Subnet Mask)’ Used to calculate network local routing entry for interface card‘:dhcp’. ‘ 3 (Router)’ Adds default route entry with the name card‘:dhcp:default’ via gateway from DHCP option. Note that only option with single route is accepted. ‘ 6 (Domain Name Server)’ Adds all servers from option value to the list of servers used during name resolution.

‘ 12 (Host Name)’ Sets environment variable ‘ net_’ ‘ _dhcp_hostname’ (see ) to the value of option. ‘ 15 (Domain Name)’ Sets environment variable ‘ net_’ ‘ _dhcp_domain’ (see ) to the value of option. ‘ 17 (Root Path)’ Sets environment variable ‘ net_’ ‘ _dhcp_rootpath’ (see ) to the value of option. ‘ 18 (Extensions Path)’ Sets environment variable ‘ net_’ ‘ _dhcp_extensionspath’ (see ) to the value of option. Next:, Previous:, Up: [][] 17 Internationalisation 17.1 Charset GRUB uses UTF-8 internally other than in rendering where some GRUB-specific appropriate representation is used. All text files (including config) are assumed to be encoded in UTF-8. 17.2 Filesystems NTFS, JFS, UDF, HFS+, exFAT, long filenames in FAT, Joliet part of ISO9660 are treated as UTF-16 as per specification.

AFS and BFS are read as UTF-8, again according to specification. BtrFS, cpio, tar, squash4, minix, minix2, minix3, ROMFS, ReiserFS, XFS, ext2, ext3, ext4, FAT (short names), RockRidge part of ISO9660, nilfs2, UFS1, UFS2 and ZFS are assumed to be UTF-8. This might be false on systems configured with legacy charset but as long as the charset used is superset of ASCII you should be able to access ASCII-named files. And it’s recommended to configure your system to use UTF-8 to access the filesystem, convmv may help with migration. ISO9660 (plain) filenames are specified as being ASCII or being described with unspecified escape sequences. GRUB assumes that the ISO9660 names are UTF-8 (since any ASCII is valid UTF-8).

There are some old CD-ROMs which use CP437 in non-compliant way. You’re still able to access files with names containing only ASCII characters on such filesystems though. You’re also able to access any file if the filesystem contains valid Joliet (UTF-16) or RockRidge (UTF-8). AFFS, SFS and HFS never use unicode and GRUB assumes them to be in Latin1, Latin1 and MacRoman respectively.

GRUB handles filesystem case-insensitivity however no attempt is performed at case conversion of international characters so e.g. A file named lowercase greek alpha is treated as different from the one named as uppercase alpha.

The filesystems in questions are NTFS (except POSIX namespace), HFS+ (configurable at mkfs time, default insensitive), SFS (configurable at mkfs time, default insensitive), JFS (configurable at mkfs time, default sensitive), HFS, AFFS, FAT, exFAT and ZFS (configurable on per-subvolume basis by property “casesensitivity”, default sensitive). On ZFS subvolumes marked as case insensitive files containing lowercase international characters are inaccessible. Also like all supported filesystems except HFS+ and ZFS (configurable on per-subvolume basis by property “normalization”, default none) GRUB makes no attempt at check of canonical equivalence so a file name u-diaresis is treated as distinct from u+combining diaresis. This however means that in order to access file on HFS+ its name must be specified in normalisation form D. On normalized ZFS subvolumes filenames out of normalisation are inaccessible. 17.3 Output terminal Firmware output console “console” on ARC and IEEE1275 are limited to ASCII. BIOS firmware console and VGA text are limited to ASCII and some pseudographics.

None of above mentioned is appropriate for displaying international and any unsupported character is replaced with question mark except pseudographics which we attempt to approximate with ASCII. EFI console on the other hand nominally supports UTF-16 but actual language coverage depends on firmware and may be very limited. The encoding used on serial can be chosen with terminfo as either ASCII, UTF-8 or “visual UTF-8”. Last one is against the specification but results in correct rendering of right-to-left on some readers which don’t have own bidi implementation.

On emu GRUB checks if charset is UTF-8 and uses it if so and uses ASCII otherwise. When using gfxterm or gfxmenu GRUB itself is responsible for rendering the text. In this case GRUB is limited by loaded fonts.

If fonts contain all required characters then bidirectional text, cursive variants and combining marks other than enclosing, half (e.g. Left half tilde or combining overline) and double ones. Ligatures aren’t supported though. This should cover European, Middle Eastern (if you don’t mind lack of lam-alif ligature in Arabic) and East Asian scripts. Notable unsupported scripts are Brahmic family and derived as well as Mongolian, Tifinagh, Korean Jamo (precomposed characters have no problem) and tonal writing (2e5-2e9). GRUB also ignores deprecated (as specified in Unicode) characters (e.g.

GRUB also doesn’t handle so called “annotation characters” If you can complete either of two lists or, better, propose a patch to improve rendering, please contact developer team. 17.4 Input terminal Firmware console on BIOS, IEEE1275 and ARC doesn’t allow you to enter non-ASCII characters. EFI specification allows for such but author is unaware of any actual implementations. Serial input is currently limited for latin1 (unlikely to change). Own keyboard implementations (at_keyboard and usb_keyboard) supports any key but work on one-char-per-keystroke. So no dead keys or advanced input method.

Also there is no keymap change hotkey. In practice it makes difficult to enter any text using non-Latin alphabet. Moreover all current input consumers are limited to ASCII.

17.5 Gettext GRUB supports being translated. For this you need to have language *.mo files in $prefix/locale, load gettext module and set “lang” variable. 17.6 Regexp Regexps work on unicode characters, however no attempt at checking cannonical equivalence has been made. Moreover the classes like [:alpha:] match only ASCII subset. 17.7 Other Currently GRUB always uses YEAR-MONTH-DAY HOUR:MINUTE:SECOND [WEEKDAY] 24-hour datetime format but weekdays are translated.

GRUB always uses the decimal number format with [0-9] as digits and. As descimal separator and no group separator. IEEE1275 aliases are matched case-insensitively except non-ASCII which is matched as binary. Similar behaviour is for matching OSBundleRequired. Since IEEE1275 aliases and OSBundleRequired don’t contain any non-ASCII it should never be a problem in practice.

Case-sensitive identifiers are matched as raw strings, no canonical equivalence check is performed. Case-insenstive identifiers are matched as RAW but additionally [a-z] is equivalent to [A-Z].

GRUB-defined identifiers use only ASCII and so should user-defined ones. Identifiers containing non-ASCII may work but aren’t supported. Only the ASCII space characters (space U+0020, tab U+000b, CR U+000d and LF U+000a) are recognised. Other unicode space characters aren’t a valid field separator.

Test (see ) tests, =, -pgt and -plt compare the strings in the lexicographical order of unicode codepoints, replicating the behaviour of test from coreutils. Environment variables and commands are listed in the same order. Next:, Up: [][] 18.1 Authentication and authorisation in GRUB By default, the boot loader interface is accessible to anyone with physical access to the console: anyone can select and edit any menu entry, and anyone can get direct access to a GRUB shell prompt. For most systems, this is reasonable since anyone with direct physical access has a variety of other ways to gain full access, and requiring authentication at the boot loader level would only serve to make it difficult to recover broken systems. However, in some environments, such as kiosks, it may be appropriate to lock down the boot loader to require authentication before performing certain operations. The ‘ password’ (see ) and ‘ password_pbkdf2’ (see ) commands can be used to define users, each of which has an associated password.

‘ password’ sets the password in plain text, requiring grub.cfg to be secure; ‘ password_pbkdf2’ sets the password hashed using the Password-Based Key Derivation Function (RFC 2898), requiring the use of grub-mkpasswd-pbkdf2 (see ) to generate password hashes. In order to enable authentication support, the ‘ superusers’ environment variable must be set to a list of usernames, separated by any of spaces, commas, semicolons, pipes, or ampersands. Superusers are permitted to use the GRUB command line, edit menu entries, and execute any menu entry. If ‘ superusers’ is set, then use of the command line and editing of menu entries are automatically restricted to superusers. Setting ‘ superusers’ to empty string effectively disables both access to CLI and editing of menu entries. Other users may be allowed to execute specific menu entries by giving a list of usernames (as above) using the --users option to the ‘ menuentry’ command (see ). If the --unrestricted option is used for a menu entry, then that entry is unrestricted.

If the --users option is not used for a menu entry, then that only superusers are able to use it. Putting this together, a typical grub.cfg fragment might look like this. Previous:, Up: [][] 18.2 Using digital signatures in GRUB GRUB’s core.img can optionally provide enforcement that all files subsequently read from disk are covered by a valid digital signature. This document does not cover how to ensure that your platform’s firmware (e.g., Coreboot) validates core.img. If environment variable check_signatures (see ) is set to enforce, then every attempt by the GRUB core.img to load another file foo implicitly invokes verify_detached foo foo.sig (see ). Foo.sig must contain a valid digital signature over the contents of foo, which can be verified with a public key currently trusted by GRUB (see, see, and see ).

If validation fails, then file foo cannot be opened. This failure may halt or otherwise impact the boot process.

GRUB uses GPG-style detached signatures (meaning that a file foo.sig will be produced when file foo is signed), and currently supports the DSA and RSA signing algorithms. A signing key can be generated as follows. # Edit /dev/shm/passphrase.txt to contain your signing key's passphrase for i in `find /boot -name '*.cfg' -or -name '*.lst' -or -name '*.mod' -or -name 'vmlinuz*' -or -name 'initrd*' -or -name 'grubenv'`; do gpg --batch --detach-sign --passphrase-fd 0 $i.

Next:, Previous:, Up: [][] 19 Platform limitations GRUB2 is designed to be portable and is actually ported across platforms. We try to keep all platforms at the level. Unfortunately some platforms are better supported than others. This is detailed in current and 2 following sections. ARC platform is unable to change datetime (firmware doesn’t seem to provide a function for it).

EMU has similar limitation. On EMU platform no serial port is available. Console charset refers only to firmware-assisted console. Gfxterm is always Unicode (see Internationalisation section for its limitations). Serial is configurable to UTF-8 or ASCII (see Internationalisation).

In case of qemu and coreboot ports the refered console is vga_text. Loongson always uses gfxterm. Most limited one is ASCII. CP437 provides additionally pseudographics. GRUB2 doesn’t use any language characters from CP437 as often CP437 is replaced by national encoding compatible only in pseudographics. Unicode is the most versatile charset which supports many languages. However the actual console may be much more limited depending on firmware On BIOS network is supported only if the image is loaded through network.

On sparc64 GRUB is unable to determine which server it was booted from. Direct ATA/AHCI support allows to circumvent various firmware limitations but isn’t needed for normal operation except on baremetal ports. AT keyboard support allows keyboard layout remapping and support for keys not available through firmware.

It isn’t needed for normal operation except baremetal ports. Speaker allows morse and spkmodem communication.

USB support provides benefits similar to ATA (for USB disks) or AT (for USB keyboards). In addition it allows USBserial.

Chainloading refers to the ability to load another bootloader through the same protocol Hints allow faster disk discovery by already knowing in advance which is the disk in question. On some platforms hints are correct unless you move the disk between boots. On other platforms it’s just an educated guess.

Note that hint failure results in just reduced performance, not a failure BadRAM is the ability to mark some of the RAM as “bad”. Note: due to protocol limitations mips-loongson (with Linux protocol) and mips-qemu_mips can use only memory up to first hole. Bootlocation is ability of GRUB to automatically detect where it boots from. “disk” means the detection is limited to detecting the disk with partition being discovered on install time.

“partition” means that disk and partiton can be automatically discovered. “file” means that boot image file name as well as disk and partition can be discovered. For consistency default install ignores partition and relies solely on disk detection. If no bootlocation discovery is available or boot and grub-root disks are different, UUID is used instead.

On ARC if no device to install to is specified, UUID is used instead as well. Next:, Previous:, Up: [][] 20 Outline Some platforms have features which allows to implement some commands useless or not implementable on others. Next:, Previous:, Up: [][] 21 Supported boot targets X86 support is summarised in the following table.

“Yes” means that the kernel works on the given platform, “crashes” means an early kernel crash which we hope will be fixed by concerned kernel developers. “no” means GRUB doesn’t load the given kernel on a given platform. “headless” means that the kernel works but lacks console drivers (you can still use serial or network console). In case of “no” and “crashes” the reason is given in footnote. BIOS Coreboot BIOS chainloading yes no (1) NTLDR yes no (1) Plan9 yes no (1) Freedos yes no (1) FreeBSD bootloader yes crashes (1) 32-bit kFreeBSD yes crashes (5) 64-bit kFreeBSD yes crashes (5) 32-bit kNetBSD yes crashes (1) 64-bit kNetBSD yes crashes 32-bit kOpenBSD yes yes 64-bit kOpenBSD yes yes Multiboot yes yes Multiboot2 yes yes 32-bit Linux (legacy protocol) yes no (1) 64-bit Linux (legacy protocol) yes no (1) 32-bit Linux (modern protocol) yes yes 64-bit Linux (modern protocol) yes yes 32-bit XNU yes?

64-bit XNU yes? Up: [][] 22.1 GRUB only offers a rescue shell GRUB’s normal start-up procedure involves setting the ‘ prefix’ environment variable to a value set in the core image by grub-install, setting the ‘ root’ variable to match, loading the ‘ normal’ module from the prefix, and running the ‘ normal’ command (see ). This command is responsible for reading /boot/grub/grub.cfg, running the menu, and doing all the useful things GRUB is supposed to do. If, instead, you only get a rescue shell, this usually means that GRUB failed to load the ‘ normal’ module for some reason.

It may be possible to work around this temporarily: for instance, if the reason for the failure is that ‘ prefix’ is wrong (perhaps it refers to the wrong device, or perhaps the path to /boot/grub was not correctly made relative to the device), then you can correct this and enter normal mode manually. # Inspect the current prefix (and other preset variables): set # Find out which devices are available: ls # Set to the correct value, which might be something like this: set prefix=(hd0,1)/grub set root=(hd0,1) insmod normal normal However, any problem that leaves you in the rescue shell probably means that GRUB was not correctly installed.

It may be more useful to try to reinstall it properly using grub-install device (see ). When doing this, there are a few things to remember: • Drive ordering in your operating system may not be the same as the boot drive ordering used by your firmware.

Do not assume that your first hard drive (e.g. ‘ /dev/sda’) is the one that your firmware will boot from. Device.map (see ) can be used to override this, but it is usually better to use UUIDs or file system labels and avoid depending on drive ordering entirely. • At least on BIOS systems, if you tell grub-install to install GRUB to a partition but GRUB has already been installed in the master boot record, then the GRUB installation in the partition will be ignored. • If possible, it is generally best to avoid installing GRUB to a partition (unless it is a special partition for the use of GRUB alone, such as the BIOS Boot Partition used on GPT). Doing this means that GRUB may stop being able to read its core image due to a file system moving blocks around, such as while defragmenting, running checks, or even during normal operation.

Installing to the whole disk device is normally more robust. • Check that GRUB actually knows how to read from the device and file system containing /boot/grub. It will not be able to read from encrypted devices with unsupported encryption scheme, nor from file systems for which support has not yet been added to GRUB. Grub-install --boot-directory=/mnt/boot /dev/sdb --recheck Recheck the device map, even if /boot/grub/device.map already exists.

You should use this option whenever you add/remove a disk into/from your computer. --no-rs-codes By default on x86 BIOS systems, grub-install will use some extra space in the bootloader embedding area for Reed-Solomon error-correcting codes. This enables GRUB to still boot successfully if some blocks are corrupted. The exact amount of protection offered is dependent on available space in the embedding area. R sectors of redundancy can tolerate up to R/2 corrupted sectors.

This redundancy may be cumbersome if attempting to cryptographically validate the contents of the bootloader embedding area, or in more modern systems with GPT-style partition tables (see ) where GRUB does not reside in any unpartitioned space outside of the MBR. Disable the Reed-Solomon codes with this option.

Mkdir -p disk/boot/grub (add extra files to disk/boot/grub) grub-mkrescue -o grub.iso disk grub-mkrescue accepts the following options: --help Print a summary of the command-line options and exit. --version Print the version number of GRUB and exit.

-o file --output= file Save output in file. This 'option' is required. --modules= modules Pre-load the named GRUB modules in the image. Multiple entries in modules should be separated by whitespace (so you will probably need to quote this for your shell). --rom-directory= dir If generating images for the QEMU or Coreboot platforms, copy the resulting qemu.img or coreboot.elf files respectively to the dir directory as well as including them in the image. --xorriso= file Use file as the xorriso program, rather than the built-in default. --grub-mkimage= file Use file as the grub-mkimage program, rather than the built-in default.

Next:, Previous:, Up: [][] 28 Invoking grub-mount The program grub-mount performs a read-only mount of any file system or file system image that GRUB understands, using GRUB’s file system drivers via FUSE. (It is only available if FUSE development files were present when GRUB was built.) This has a number of uses: • It provides a convenient way to check how GRUB will view a file system at boot time. You can use normal command-line tools to compare that view with that of your operating system, making it easy to find bugs. • It offers true read-only mounts. Linux does not have these for journalling file systems, because it will always attempt to replay the journal at mount time; while you can temporarily mark the block device read-only to avoid this, that causes the mount to fail.

Since GRUB intentionally contains no code for writing to file systems, it can easily provide a guaranteed read-only mount mechanism. • It allows you to examine any file system that GRUB understands without needing to load additional modules into your running kernel, which may be useful in constrained environments such as installers. • Since it can examine file system images (contained in regular files) just as easily as file systems on block devices, you can use it to inspect any file system image that GRUB understands with only enough privileges to use FUSE, even if nobody has yet written a FUSE module specifically for that file system type. Using grub-mount is normally as simple as. Grub-mount /dev/sda1 /mnt grub-mount must be given one or more images and a mount point as non-option arguments (if it is given more than one image, it will treat them as a RAID set), and also accepts the following options: --help Print a summary of the command-line options and exit.

--version Print the version number of GRUB and exit. -C --crypto Mount encrypted devices, prompting for a passphrase if necessary.

-d string --debug= string Show debugging output for conditions matching string. -K prompt file --zfs-key=prompt file Load a ZFS encryption key. If you use ‘ prompt’ as the argument, grub-mount will read a passphrase from the terminal; otherwise, it will read key material from the specified file. -r device --root= device Set the GRUB root device to device.

You do not normally need to set this; grub-mount will automatically set the root device to the root of the supplied file system. If device is just a number, then it will be treated as a partition number within the supplied image. This means that, if you have an image of an entire disk in disk.img, then you can use this command to mount its second partition. Grub-probe --target=fs /boot/grub grub-probe --target=drive --device /dev/sda1 grub-probe must be given a path or device as a non-option argument, and also accepts the following options: --help Print a summary of the command-line options and exit. --version Print the version number of GRUB and exit.

-d --device If this option is given, then the non-option argument is a system device name (such as ‘ /dev/sda1’), and grub-probe will print information about that device. If it is not given, then the non-option argument is a filesystem path (such as ‘ /boot/grub’), and grub-probe will print information about the device containing that part of the filesystem. -m file --device-map= file Use file as the device map (see ) rather than the default, usually ‘ /boot/grub/device.map’.

-t target --target= target Print information about the given path or device as defined by target. The available targets and their meanings are: ‘ fs’ GRUB filesystem module. ‘ fs_uuid’ Filesystem Universally Unique Identifier (UUID).

‘ fs_label’ Filesystem label. ‘ drive’ GRUB device name.

‘ device’ System device name. ‘ partmap’ GRUB partition map module.

‘ abstraction’ GRUB abstraction module (e.g. ‘ cryptodisk_uuid’ Crypto device UUID. ‘ msdos_parttype’ MBR partition type code (two hexadecimal digits). ‘ hints_string’ A string of platform search hints suitable for passing to the search command (see ). ‘ bios_hints’ Search hints for the PC BIOS platform.

‘ ieee1275_hints’ Search hints for the IEEE1275 platform. ‘ baremetal_hints’ Search hints for platforms where disks are addressed directly rather than via firmware.

‘ efi_hints’ Search hints for the EFI platform. ‘ arc_hints’ Search hints for the ARC platform. ‘ compatibility_hint’ A guess at a reasonable GRUB drive name for this device, which may be used as a fallback if the search command fails. ‘ disk’ System device name for the whole disk. -v --verbose Print verbose messages. Next:, Previous:, Up: [][] Appendix A How to obtain and build GRUB Caution: GRUB requires binutils-2.9.1.0.23 or later because the GNU assembler has been changed so that it can produce real 16bits machine code between 2.9.1 and 2.9.1.0.x.

See, to obtain information on how to get the latest version. GRUB is available from the GNU alpha archive site or any of its mirrors. The file will be named grub-version.tar.gz. The current version is 2.02, so the file you should grab is: To unbundle GRUB use the instruction.

Next:, Previous:, Up: [][] Appendix B Reporting bugs These are the guideline for how to report bugs. Take a look at this list below before you submit bugs: • Before getting unsettled, read this manual through and through. Also, see the. • Always mention the information on your GRUB. The version number and the configuration are quite important.

If you build it yourself, write the options specified to the configure script and your operating system, including the versions of gcc and binutils. • If you have trouble with the installation, inform us of how you installed GRUB. Don’t omit error messages, if any. Just ‘ GRUB hangs up when it boots’ is not enough. The information on your hardware is also essential. These are especially important: the geometries and the partition tables of your hard disk drives and your BIOS. • If GRUB cannot boot your operating system, write down everything you see on the screen.

Don’t paraphrase them, like ‘ The foo OS crashes with GRUB, even though it can boot with the bar boot loader just fine’. Mention the commands you executed, the messages printed by them, and information on your operating system including the version number. • Explain what you wanted to do. It is very useful to know your purpose and your wish, and how GRUB didn’t satisfy you. • If you can investigate the problem yourself, please do. That will give you and us much more information on the problem. Attaching a patch is even better.

When you attach a patch, make the patch in unified diff format, and write ChangeLog entries. But, even when you make a patch, don’t forget to explain the problem, so that we can understand what your patch is for. • Write down anything that you think might be related.

Please understand that we often need to reproduce the same problem you encountered in our environment. So your information should be sufficient for us to do the same thing—Don’t forget that we cannot see your computer directly. If you are not sure whether to state a fact or leave it out, state it! Reporting too many things is much better than omitting something important. If you follow the guideline above, submit a report to the. Alternatively, you can submit a report via electronic mail to, but we strongly recommend that you use the Bug Tracking System, because e-mail can be passed over easily.

Once we get your report, we will try to fix the bugs. Copyright © 2000,2001,2002 Free Software Foundation, Inc. 51 Franklin St, Fifth Floor, Boston, MA, USA Everyone is permitted to copy and distribute verbatim copies of this license document, but changing it is not allowed.

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A copy of the license is included in the section entitled ``GNU Free Documentation License'. If you have Invariant Sections, Front-Cover Texts and Back-Cover Texts, replace the “with.Texts.” line with this. With the Invariant Sections being list their titles, with the Front-Cover Texts being list, and with the Back-Cover Texts being list. If you have Invariant Sections without Cover Texts, or some other combination of the three, merge those two alternatives to suit the situation. If your document contains nontrivial examples of program code, we recommend releasing these examples in parallel under your choice of free software license, such as the GNU General Public License, to permit their use in free software. [][] Footnotes chain-load is the mechanism for loading unsupported operating systems by loading another boot loader. It is typically used for loading DOS or Windows.

The NetBSD/i386 kernel is Multiboot-compliant, but lacks support for Multiboot modules. Only CRC32 data integrity check is supported (xz default is CRC64 so one should use –check=crc32 option). LZMA BCJ filters are supported. There are a few pathological cases where loading a very badly organized ELF kernel might take longer, but in practice this never happen.

The LInux LOader, a boot loader that everybody uses, but nobody likes. El Torito is a specification for bootable CD using BIOS functions. Currently a backslash-newline pair within a variable name is not handled properly, so use this feature with some care. However, this behavior will be changed in the future version, in a user-invisible way.

Example 1: Result. OpenSCAD font list dialog OpenSCAD includes the fonts Liberation Mono, Liberation Sans, Liberation Sans Narrow and Liberation Serif. Hence, as fonts in general differ by platform type, use of these included fonts is likely to be portable across platforms. For common/casual text usage, the specification of one of these fonts is recommended for this reason.

Liberation Sans is the default font to encourage this. In addition to the installed fonts, it's possible to add project specific font files. Supported font file formats are Fonts (*.ttf) and Fonts (*.otf). The files need to be registered with use. Use After the registration, the font will also be listed in the font list dialog, so in case logical name of a font is unknown, it can be looked up there are it was registered. Right-hand grip rule You must use parameter names due to a backward compatibility issue.

Convexity If the extrusion fails for a non-trival 2D shape, try setting the convexity parameter (the default is not 10, but 10 is a 'good' value to try). See explanation further down. Angle [ Note: Requires version 2016.XX] Defaults to 360. Specifies the number of degrees to sweep, starting at the positive X axis. The direction of the sweep follows the, hence a negative angle will sweep clockwise.

Examples [ ]. OpenSCAD - a hook translate([0,60,0]) rotate_extrude(angle=270, convexity=10) translate([40, 0]) circle(10); rotate_extrude(angle=90, convexity=10) translate([20, 0]) circle(10); translate([20,0,0]) rotate([90,0,0]) cylinder(r=10,h=80); Extruding a Polygon [ ] Extrusion can also be performed on polygons with points chosen by the user. Here is a simple polygon and its 200 step rotational extrusion. (Note it has been rotated 90 degrees to show how the rotation will look; the rotate_extrude() needs it flat). Rotate([90,0,0]) polygon( points=[[0,0],[2,1],[1,2],[1,3],[3,4],[0,5]] ); rotate_extrude($fn=200) polygon( points=[[0,0],[2,1],[1,2],[1,3],[3,4],[0,5]] ).

→ → For more information on polygons, please see:. Description of extrude parameters [ ] Extrude parameters for all extrusion modes [ ] convexity Integer. The convexity parameter specifies the maximum number of front sides (back sides) a ray intersecting the object might penetrate. This parameter is only needed for correctly displaying the object in OpenCSG preview mode and has no effect on the polyhedron rendering. This image shows a 2D shape with a convexity of 4, as the ray indicated in red crosses the 2D shape a maximum of 4 times. The convexity of a 3D shape would be determined in a similar way.

Setting it to 10 should work fine for most cases. Extrude parameters for linear extrusion only [ ] height The extrusion height center If true the solid will be centered after extrusion twist The extrusion twist in degrees slices Similar to special variable $fn without being passed down to the child 2D shape. Scale Scales the 2D shape by this value over the height of the extrusion. [ ] With the import() and extrusion modules it is possible to convert 2D objects read from DXF files to 3D objects. Linear Extrude [ ] Example of linear extrusion of a 2D object imported from a DXF file.

Linear_extrude(height = fanwidth, center = true, convexity = 10) import (file = 'example009.dxf', layer = 'fan_top'); Rotate Extrude [ ] Example of rotational extrusion of a 2D object imported from a DXF file. Rotate_extrude(convexity = 10) import (file = 'example009.dxf', layer = 'fan_side', origin = fan_side_center); Getting Inkscape to work [ ] Inkscape is an open source drawing program. Tutorials for transferring 2d DXF drawings from Inkscape to OpenSCAD are available here: • (Very simple, needs path segments to be straight lines) • (More complicated, involves conversion to Postscript) • (Better DXF Export, native support for bezier curves) • (even better support, works as of, see link below registration window.

Note: As of 6/17/15 only works with version 0.48.5 or earlier of inkscape, due to a breaking change made in 0.91.) • (Convert any 2D image to a 3D object using OpenSCAD).