diff --git a/ChangeLog b/ChangeLog index 4767763e3..a47abd4a3 100644 --- a/ChangeLog +++ b/ChangeLog @@ -1,3 +1,9 @@ +2009-08-07 Robert Millan + + * docs/grub.texi: Major overhaul. Remove all sections that are + specific to GRUB Legacy, or mostly composed of Legacy-specific + information. + 2009-08-07 Robert Millan * docs/version.texi: New file. Provides version information for diff --git a/docs/grub.texi b/docs/grub.texi index 1abeb242c..e3f412565 100644 --- a/docs/grub.texi +++ b/docs/grub.texi @@ -34,14 +34,9 @@ Invariant Sections. @direntry * GRUB: (grub). The GRand Unified Bootloader * grub-install: (grub)Invoking grub-install. Install GRUB on your drive -* grub-md5-crypt: (grub)Invoking grub-md5-crypt. Encrypt a password - in MD5 format * grub-terminfo: (grub)Invoking grub-terminfo. Generate a terminfo command from a terminfo name -* grub-set-default: (grub)Invoking grub-set-default. Set a default boot - entry -* mbchk: (grub)Invoking mbchk. Check for the format of a Multiboot kernel @end direntry @setchapternewpage odd @@ -86,7 +81,6 @@ This edition documents version @value{VERSION}. * Network:: Downloading OS images from a network * Serial terminal:: Using GRUB via a serial line * Preset Menu:: Embedding a configuration file into GRUB -* Security:: Improving the security * Images:: GRUB image files * Filesystem:: Filesystem syntax and semantics * Interface:: The menu and the command-line @@ -94,10 +88,7 @@ This edition documents version @value{VERSION}. * Troubleshooting:: Error messages produced by GRUB * Invoking the grub shell:: How to use the grub shell * Invoking grub-install:: How to use the GRUB installer -* Invoking grub-md5-crypt:: How to generate a cryptic password * Invoking grub-terminfo:: How to generate a terminfo command -* Invoking grub-set-default:: How to set a default boot entry -* Invoking mbchk:: How to use the Multiboot checker * Obtaining and Building GRUB:: How to obtain and build GRUB * Reporting bugs:: Where you should send a bug report * Future:: Some future plans on GRUB @@ -158,11 +149,6 @@ partition, and a file name (@pxref{Naming convention}) to GRUB, how to install GRUB on your drive (@pxref{Installation}), and how to boot your OSes (@pxref{Booting}), step by step. -Besides the GRUB boot loader itself, there is a @dfn{grub shell} -@command{grub} (@pxref{Invoking the grub shell}) which can be run when -you are in your operating system. It emulates the boot loader and can -be used for installing the boot loader. - @node History @section History of GRUB @@ -458,119 +444,17 @@ have an emergency boot disk ready, so that you can rescue your computer if, by any chance, your hard drive becomes unusable (unbootable). GRUB comes with boot images, which are normally put in the directory -@file{/usr/lib/grub/i386-pc}. If you do not use grub-install, then -you need to copy the files @file{stage1}, @file{stage2}, and -@file{*stage1_5} to the directory @file{/boot/grub}, and run the -@command{grub-set-default} (@pxref{Invoking grub-set-default}) if you -intend to use @samp{default saved} (@pxref{default}) in your -configuration file. Hereafter, the directory where GRUB images are +@file{/usr/lib/grub/i386-pc}. Hereafter, the directory where GRUB images are initially placed (normally @file{/usr/lib/grub/i386-pc}) will be called the @dfn{image directory}, and the directory where the boot loader needs to find them (usually @file{/boot/grub}) will be called the @dfn{boot directory}. @menu -* Creating a GRUB boot floppy:: -* Installing GRUB natively:: * Installing GRUB using grub-install:: -* Making a GRUB bootable CD-ROM:: @end menu -@node Creating a GRUB boot floppy -@section Creating a GRUB boot floppy - -To create a GRUB boot floppy, you need to take the files @file{stage1} -and @file{stage2} from the image directory, and write them to the first -and the second block of the floppy disk, respectively. - -@strong{Caution:} This procedure will destroy any data currently stored -on the floppy. - -On a UNIX-like operating system, that is done with the following -commands: - -@example -@group -# @kbd{cd /usr/lib/grub/i386-pc} -# @kbd{dd if=stage1 of=/dev/fd0 bs=512 count=1} -1+0 records in -1+0 records out -# @kbd{dd if=stage2 of=/dev/fd0 bs=512 seek=1} -153+1 records in -153+1 records out -# -@end group -@end example - -The device file name may be different. Consult the manual for your OS. - - -@node Installing GRUB natively -@section Installing GRUB natively - -@strong{Caution:} Installing GRUB's stage1 in this manner will erase the -normal boot-sector used by an OS. - -GRUB can currently boot GNU Mach, Linux, FreeBSD, NetBSD, and OpenBSD -directly, so using it on a boot sector (the first sector of a -partition) should be okay. But generally, it would be a good idea to -back up the first sector of the partition on which you are installing -GRUB's stage1. This isn't as important if you are installing GRUB on -the first sector of a hard disk, since it's easy to reinitialize it -(e.g. by running @samp{FDISK /MBR} from DOS). - -If you decide to install GRUB in the native environment, which is -definitely desirable, you'll need to create a GRUB boot disk, and -reboot your computer with it. Otherwise, see @ref{Installing GRUB using -grub-install}. - -Once started, GRUB will show the command-line interface -(@pxref{Command-line interface}). First, set the GRUB's @dfn{root -device}@footnote{Note that GRUB's root device doesn't necessarily mean -your OS's root partition; if you need to specify a root partition for -your OS, add the argument into the command @command{kernel}.} to the -partition containing the boot directory, like this: - -@example -grub> @kbd{root (hd0,0)} -@end example - -If you are not sure which partition actually holds this directory, use the -command @command{find} (@pxref{find}), like this: - -@example -grub> @kbd{find /boot/grub/stage1} -@end example - -This will search for the file name @file{/boot/grub/stage1} and show the -devices which contain the file. - -Once you've set the root device correctly, run the command -@command{setup} (@pxref{setup}): - -@example -grub> @kbd{setup (hd0)} -@end example - -This command will install the GRUB boot loader on the Master Boot -Record (MBR) of the first drive. If you want to put GRUB into the boot -sector of a partition instead of putting it in the MBR, specify the -partition into which you want to install GRUB: - -@example -grub> @kbd{setup (hd0,0)} -@end example - -If you install GRUB into a partition or a drive other than the first -one, you must chain-load GRUB from another boot loader. Refer to the -manual for the boot loader to know how to chain-load GRUB. - -After using the setup command, you will boot into GRUB without the -GRUB floppy. See the chapter @ref{Booting} to find out how to boot -your operating systems from GRUB. - - @node Installing GRUB using grub-install @section Installing GRUB using grub-install @@ -722,7 +606,6 @@ magic. @menu * General boot methods:: How to boot OSes with GRUB generally * OS-specific notes:: Notes on some operating systems -* Making your system robust:: How to make your system robust @end menu @@ -753,71 +636,9 @@ 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 (@pxref{Chain-loading}). -Generally, GRUB can boot any Multiboot-compliant OS in the following -steps: +FIXME: this section is incomplete. @enumerate -@item -Set GRUB's root device to the drive where the OS images are stored with -the command @command{root} (@pxref{root}). - -@item -Load the kernel image with the command @command{kernel} (@pxref{kernel}). - -@item -If you need modules, load them with the command @command{module} -(@pxref{module}) or @command{modulenounzip} (@pxref{modulenounzip}). - -@item -Run the command @command{boot} (@pxref{boot}). -@end enumerate - -Linux, FreeBSD, NetBSD and OpenBSD can be booted in a similar -manner. You load a kernel image with the command @command{kernel} and -then run the command @command{boot}. If the kernel requires some -parameters, just append the parameters to @command{kernel}, after the -file name of the kernel. Also, please refer to @ref{OS-specific notes}, -for information on your OS-specific issues. - - -@node Chain-loading -@subsection Load another boot loader to boot unsupported operating systems - -If you want to boot an unsupported operating system (e.g. Windows 95), -chain-load a boot loader for the operating system. Normally, the boot -loader is embedded in the @dfn{boot sector} of the partition on which -the operating system is installed. - -@enumerate -@item -Set GRUB's root device to the partition by the command -@command{rootnoverify} (@pxref{rootnoverify}): - -@example -grub> @kbd{rootnoverify (hd0,0)} -@end example - -@item -Set the @dfn{active} flag in the partition using the command -@command{makeactive}@footnote{This is not necessary for most of the -modern operating systems.} (@pxref{makeactive}): - -@example -grub> @kbd{makeactive} -@end example - -@item -Load the boot loader with the command @command{chainloader} -(@pxref{chainloader}): - -@example -grub> @kbd{chainloader +1} -@end example - -@samp{+1} indicates that GRUB should read one sector from the start of -the partition. The complete description about this syntax can be found -in @ref{Block list syntax}. - @item Run the command @command{boot} (@pxref{boot}). @end enumerate @@ -835,12 +656,6 @@ Here, we describe some caveats on several operating systems. @menu * GNU/Hurd:: * GNU/Linux:: -* FreeBSD:: -* NetBSD:: -* OpenBSD:: -* DOS/Windows:: -* SCO UnixWare:: -* QNX:: @end menu @@ -851,22 +666,9 @@ Since GNU/Hurd is Multiboot-compliant, it is easy to boot it; there is nothing special about it. But do not forget that you have to specify a root partition to the kernel. +FIXME: this section is incomplete. + @enumerate -@item -Set GRUB's root device to the same drive as GNU/Hurd's. Probably the -command @code{find /boot/gnumach} or similar can help you -(@pxref{find}). - -@item -Load the kernel and the module, like this: - -@example -@group -grub> @kbd{kernel /boot/gnumach root=hd0s1} -grub> @kbd{module /boot/serverboot} -@end group -@end example - @item Run the command @command{boot} (@pxref{boot}). @end enumerate @@ -878,35 +680,11 @@ Run the command @command{boot} (@pxref{boot}). It is relatively easy to boot GNU/Linux from GRUB, because it somewhat resembles to boot a Multiboot-compliant OS. +FIXME: this section is incomplete. + @enumerate @item -Set GRUB's root device to the same drive as GNU/Linux's. Probably the -command @code{find /vmlinuz} or similar can help you (@pxref{find}). - -@item -Load the kernel: - -@example -grub> @kbd{kernel /vmlinuz root=/dev/hda1} -@end example - -If you need to specify some kernel parameters, just append them to the -command. For example, to set @option{vga} to @samp{ext}, do this: - -@example -grub> @kbd{kernel /vmlinuz root=/dev/hda1 vga=ext} -@end example - -See the documentation in the Linux source tree for complete -information on the available options. - -@item -If you use an initrd, execute the command @command{initrd} -(@pxref{initrd}) after @command{kernel}: - -@example -grub> @kbd{initrd /initrd} -@end example +Set GRUB's root device to the same drive as GNU/Linux's. @item Finally, run the command @command{boot} (@pxref{boot}). @@ -919,617 +697,6 @@ the size, run the command @command{uppermem} @emph{before} loading the kernel. @xref{uppermem}, for more information. -@node FreeBSD -@subsection FreeBSD - -GRUB can load the kernel directly, either in ELF or a.out format. But -this is not recommended, since FreeBSD's bootstrap interface sometimes -changes heavily, so GRUB can't guarantee to pass kernel parameters -correctly. - -Thus, we'd recommend loading the very flexible loader -@file{/boot/loader} instead. See this example: - -@example -@group -grub> @kbd{root (hd0,a)} -grub> @kbd{kernel /boot/loader} -grub> @kbd{boot} -@end group -@end example - - -@node NetBSD -@subsection NetBSD - -GRUB can load NetBSD a.out and ELF directly, follow these steps: - -@enumerate -@item -Set GRUB's root device with @command{root} (@pxref{root}). - -@item -Load the kernel with @command{kernel} (@pxref{kernel}). You should -append the ugly option @option{--type=netbsd}, if you want to load an -ELF kernel, like this: - -@example -grub> @kbd{kernel --type=netbsd /netbsd-elf} -@end example - -@item -Run @command{boot} (@pxref{boot}). -@end enumerate - -For now, however, GRUB doesn't allow you to pass kernel parameters, so -it may be better to chain-load it instead. For more information, please -see @ref{Chain-loading}. - - -@node OpenBSD -@subsection OpenBSD - -The booting instruction is exactly the same as for NetBSD -(@pxref{NetBSD}). - - -@node DOS/Windows -@subsection DOS/Windows - -GRUB cannot boot DOS or Windows directly, so you must chain-load them -(@pxref{Chain-loading}). 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 @command{map} (@pxref{map}), like this: - -@example -@group -grub> @kbd{map (hd0) (hd1)} -grub> @kbd{map (hd1) (hd0)} -@end group -@end example - -This performs a @dfn{virtual} swap between your first and second hard -drive. - -@strong{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 @dfn{hide}s a DOS (or Windows) partition (@pxref{hide}), DOS (or -Windows) will ignore the partition. If GRUB @dfn{unhide}s a DOS (or -Windows) partition (@pxref{unhide}), 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: - -@example -@group -grub> @kbd{unhide (hd0,0)} -grub> @kbd{hide (hd0,1)} -grub> @kbd{rootnoverify (hd0,0)} -grub> @kbd{chainloader +1} -grub> @kbd{makeactive} -grub> @kbd{boot} -@end group -@end example - - -@node SCO UnixWare -@subsection SCO UnixWare - -It is known that the signature in the boot loader for SCO UnixWare is -wrong, so you will have to specify the option @option{--force} to -@command{chainloader} (@pxref{chainloader}), like this: - -@example -@group -grub> @kbd{rootnoverify (hd1,0)} -grub> @kbd{chainloader --force +1} -grub> @kbd{makeactive} -grub> @kbd{boot} -@end group -@end example - - -@node QNX -@subsection QNX - -QNX seems to use a bigger boot loader, so you need to boot it up, like -this: - -@example -@group -grub> @kbd{rootnoverify (hd1,1)} -grub> @kbd{chainloader +4} -grub> @kbd{boot} -@end group -@end example - - -@node Making your system robust -@section How to make your system robust - -When you test a new kernel or a new OS, it is important to make sure -that your computer can boot even if the new system is unbootable. This -is crucial especially if you maintain servers or remote systems. To -accomplish this goal, you need to set up two things: - -@enumerate -@item -You must maintain a system which is always bootable. For instance, if -you test a new kernel, you need to keep a working kernel in a -different place. And, it would sometimes be very nice to even have a -complete copy of a working system in a different partition or disk. - -@item -You must direct GRUB to boot a working system when the new system -fails. This is possible with the @dfn{fallback} system in GRUB. -@end enumerate - -The former requirement is very specific to each OS, so this -documentation does not cover that topic. It is better to consult some -backup tools. - -So let's see the GRUB part. There are two possibilities: one of them -is quite simple but not very robust, and the other is a bit complex to -set up but probably the best solution to make sure that your system -can start as long as GRUB itself is bootable. - -@menu -* Booting once-only:: -* Booting fallback systems:: -@end menu - - -@node Booting once-only -@subsection Booting once-only - -You can teach GRUB to boot an entry only at next boot time. Suppose -that your have an old kernel @file{old_kernel} and a new kernel -@file{new_kernel}. You know that @file{old_kernel} can boot -your system correctly, and you want to test @file{new_kernel}. - -To ensure that your system will go back to the old kernel even if the -new kernel fails (e.g. it panics), you can specify that GRUB should -try the new kernel only once and boot the old kernel after that. - -First, modify your configuration file. Here is an example: - -@example -@group -default saved # This is important!!! -timeout 10 - -title the old kernel -root (hd0,0) -kernel /old_kernel -savedefault - -title the new kernel -root (hd0,0) -kernel /new_kernel -savedefault 0 # This is important!!! -@end group -@end example - -Note that this configuration file uses @samp{default saved} -(@pxref{default}) at the head and @samp{savedefault 0} -(@pxref{savedefault}) in the entry for the new kernel. This means -that GRUB boots a saved entry by default, and booting the entry for the -new kernel saves @samp{0} as the saved entry. - -With this configuration file, after all, GRUB always tries to boot the -old kernel after it booted the new one, because @samp{0} is the entry -of @code{the old kernel}. - -The next step is to tell GRUB to boot the new kernel at next boot -time. For this, execute @command{grub-set-default} (@pxref{Invoking -grub-set-default}): - -@example -# @kbd{grub-set-default 1} -@end example - -This command sets the saved entry to @samp{1}, that is, to the new -kernel. - -This method is useful, but still not very robust, because GRUB stops -booting, if there is any error in the boot entry, such that the new -kernel has an invalid executable format. Thus, it it even better to -use the @dfn{fallback} mechanism of GRUB. Look at next subsection for -this feature. - - -@node Booting fallback systems -@subsection Booting fallback systems - -GRUB supports a fallback mechanism of booting one or more other -entries if a default boot entry fails. You can specify multiple -fallback entries if you wish. - -Suppose that you have three systems, @samp{A}, @samp{B} and -@samp{C}. @samp{A} is a system which you want to boot by -default. @samp{B} is a backup system which is supposed to boot -safely. @samp{C} is another backup system which is used in case where -@samp{B} is broken. - -Then you may want GRUB to boot the first system which is bootable -among @samp{A}, @samp{B} and @samp{C}. A configuration file can be -written in this way: - -@example -@group -default saved # This is important!!! -timeout 10 -fallback 1 2 # This is important!!! - -title A -root (hd0,0) -kernel /kernel -savedefault fallback # This is important!!! - -title B -root (hd1,0) -kernel /kernel -savedefault fallback # This is important!!! - -title C -root (hd2,0) -kernel /kernel -savedefault -@end group -@end example - -Note that @samp{default saved} (@pxref{default}), @samp{fallback 1 2} -and @samp{savedefault fallback} are used. GRUB will boot a saved entry -by default and save a fallback entry as next boot entry with this -configuration. - -When GRUB tries to boot @samp{A}, GRUB saves @samp{1} as next boot -entry, because the command @command{fallback} specifies that @samp{1} -is the first fallback entry. The entry @samp{1} is @samp{B}, so GRUB -will try to boot @samp{B} at next boot time. - -Likewise, when GRUB tries to boot @samp{B}, GRUB saves @samp{2} as -next boot entry, because @command{fallback} specifies @samp{2} as next -fallback entry. This makes sure that GRUB will boot @samp{C} after -booting @samp{B}. - -It is noteworthy that GRUB uses fallback entries both when GRUB -itself fails in booting an entry and when @samp{A} or @samp{B} fails -in starting up your system. So this solution ensures that your system -is started even if GRUB cannot find your kernel or if your kernel -panics. - -However, you need to run @command{grub-set-default} (@pxref{Invoking -grub-set-default}) when @samp{A} starts correctly or you fix @samp{A} -after it crashes, since GRUB always sets next boot entry to a fallback -entry. You should run this command in a startup script such as -@file{rc.local} to boot @samp{A} by default: - -@example -# @kbd{grub-set-default 0} -@end example - -where @samp{0} is the number of the boot entry for the system -@samp{A}. - -If you want to see what is current default entry, you can look at the -file @file{/boot/grub/default} (or @file{/grub/default} in -some systems). Because this file is plain-text, you can just -@command{cat} this file. But it is strongly recommended @strong{not to -modify this file directly}, because GRUB may fail in saving a default -entry in this file, if you change this file in an unintended -manner. Therefore, you should use @command{grub-set-default} when you -need to change the default entry. - - -@node Configuration -@chapter Configuration - -You've probably noticed that you need to type several commands to boot your -OS. There's a solution to that - GRUB provides a menu interface -(@pxref{Menu interface}) from which you can select an item (using arrow -keys) that will do everything to boot an OS. - -To enable the menu, you need a configuration file, -@file{menu.lst} under the boot directory. We'll analyze an example -file. - -The file first contains some general settings, the menu interface -related options. You can put these commands (@pxref{Menu-specific -commands}) before any of the items (starting with @command{title} -(@pxref{title})). - -@example -@group -# -# Sample boot menu configuration file -# -@end group -@end example - -As you may have guessed, these lines are comments. Lines starting with a -hash character (@samp{#}), and blank lines, are ignored by GRUB. - -@example -@group -# By default, boot the first entry. -default 0 -@end group -@end example - -The first entry (here, counting starts with number zero, not one!) will -be the default choice. - -@example -@group -# Boot automatically after 30 secs. -timeout 30 -@end group -@end example - -As the comment says, GRUB will boot automatically in 30 seconds, unless -interrupted with a keypress. - -@example -@group -# Fallback to the second entry. -fallback 1 -@end group -@end example - -If, for any reason, the default entry doesn't work, fall back to the -second one (this is rarely used, for obvious reasons). - -Note that the complete descriptions of these commands, which are menu -interface specific, can be found in @ref{Menu-specific -commands}. Other descriptions can be found in @ref{Commands}. - -Now, on to the actual OS definitions. You will see that each entry -begins with a special command, @command{title} (@pxref{title}), and the -action is described after it. Note that there is no command -@command{boot} (@pxref{boot}) at the end of each item. That is because -GRUB automatically executes @command{boot} if it loads other commands -successfully. - -The argument for the command @command{title} is used to display a short -title/description of the entry in the menu. Since @command{title} -displays the argument as is, you can write basically anything there. - -@example -@group -# For booting GNU/Hurd -title GNU/Hurd -root (hd0,0) -kernel /boot/gnumach.gz root=hd0s1 -module /boot/serverboot.gz -@end group -@end example - -This boots GNU/Hurd from the first hard disk. - -@example -@group -# For booting GNU/Linux -title GNU/Linux -kernel (hd1,0)/vmlinuz root=/dev/hdb1 -@end group -@end example - -This boots GNU/Linux, but from the second hard disk. - -@example -@group -# For booting Mach (getting kernel from floppy) -title Utah Mach4 multiboot -root (hd0,2) -pause Insert the diskette now^G!! -kernel (fd0)/boot/kernel root=hd0s3 -module (fd0)/boot/bootstrap -@end group -@end example - -This boots Mach with a kernel on a floppy, but the root filesystem at -hd0s3. It also contains a @command{pause} line (@pxref{pause}), which -will cause GRUB to display a prompt and delay, before actually executing -the rest of the commands and booting. - -@example -@group -# For booting FreeBSD -title FreeBSD -root (hd0,2,a) -kernel /boot/loader -@end group -@end example - -This item will boot FreeBSD kernel loaded from the @samp{a} partition of -the third @sc{pc} slice of the first hard disk. - -@example -@group -# For booting OS/2 -title OS/2 -root (hd0,1) -makeactive -# chainload OS/2 bootloader from the first sector -chainloader +1 -# This is similar to "chainload", but loads a specific file -#chainloader /boot/chain.os2 -@end group -@end example - -This will boot OS/2, using a chain-loader (@pxref{Chain-loading}). - -@example -@group -# For booting Windows NT or Windows95 -title Windows NT / Windows 95 boot menu -root (hd0,0) -makeactive -chainloader +1 -# For loading DOS if Windows NT is installed -# chainload /bootsect.dos -@end group -@end example - -The same as the above, but for Windows. - -@example -@group -# For installing GRUB into the hard disk -title Install GRUB into the hard disk -root (hd0,0) -setup (hd0) -@end group -@end example - -This will just (re)install GRUB onto the hard disk. - -@example -# Change the colors. -title Change the colors -color light-green/brown blink-red/blue -@end example - -In the last entry, the command @command{color} is used (@pxref{color}), -to change the menu colors (try it!). This command is somewhat special, -because it can be used both in the command-line and in the menu. GRUB -has several such commands, see @ref{General commands}. - -We hope that you now understand how to use the basic features of -GRUB. To learn more about GRUB, see the following chapters. - - -@node Network -@chapter Downloading OS images from a network - -Although GRUB is a disk-based boot loader, it does provide network -support. To use the network support, you need to enable at least one -network driver in the GRUB build process. For more information please -see @file{netboot/README.netboot} in the source distribution. - -@menu -* General usage of network support:: -* Diskless:: -@end menu - - -@node General usage of network support -@section How to set up your network - -GRUB requires a file server and optionally a server that will assign an -IP address to the machine on which GRUB is running. For the former, only -TFTP is supported at the moment. The latter is either BOOTP, DHCP or a -RARP server@footnote{RARP is not advised, since it cannot serve much -information}. It is not necessary to run both the servers on one -computer. How to configure these servers is beyond the scope of this -document, so please refer to the manuals specific to those -protocols/servers. - -If you decided to use a server to assign an IP address, set up the -server and run @command{bootp} (@pxref{bootp}), @command{dhcp} -(@pxref{dhcp}) or @command{rarp} (@pxref{rarp}) for BOOTP, DHCP or RARP, -respectively. Each command will show an assigned IP address, a netmask, -an IP address for your TFTP server and a gateway. If any of the -addresses is wrong or it causes an error, probably the configuration of -your servers isn't set up properly. - -Otherwise, run @command{ifconfig}, like this: - -@example -grub> @kbd{ifconfig --address=192.168.110.23 --server=192.168.110.14} -@end example - -You can also use @command{ifconfig} in conjuction with @command{bootp}, -@command{dhcp} or @command{rarp} (e.g. to reassign the server address -manually). @xref{ifconfig}, for more details. - -Finally, download your OS images from your network. The network can be -accessed using the network drive @samp{(nd)}. Everything else is very -similar to the normal instructions (@pxref{Booting}). - -Here is an example: - -@example -@group -grub> @kbd{bootp} -Probing... [NE*000] -NE2000 base ... -Address: 192.168.110.23 Netmask: 255.255.255.0 -Server: 192.168.110.14 Gateway: 192.168.110.1 - -grub> @kbd{root (nd)} -grub> @kbd{kernel /tftproot/gnumach.gz root=sd0s1} -grub> @kbd{module /tftproot/serverboot.gz} -grub> @kbd{boot} -@end group -@end example - - -@node Diskless -@section Booting from a network - -It is sometimes very useful to boot from a network, especially when you -use a machine which has no local disk. In this case, you need to obtain -a kind of Net Boot @sc{rom}, such as a PXE @sc{rom} or a free software -package like Etherboot. Such a Boot @sc{rom} first boots the machine, -sets up the network card installed into the machine, and downloads a -second stage boot image from the network. Then, the second image will -try to boot an operating system actually from the network. - -GRUB provides two second stage images, @file{nbgrub} and -@file{pxegrub} (@pxref{Images}). These images are the same as the -normal Stage 2, except that they set up a network automatically, and try -to load a configuration file from the network, if specified. The usage -is very simple: If the machine has a PXE @sc{rom}, use -@file{pxegrub}. If the machine has an NBI loader such as Etherboot, use -@file{nbgrub}. There is no difference between them except their -formats. Since the way to load a second stage image you want to use -should be described in the manual on your Net Boot @sc{rom}, please -refer to the manual, for more information. - -However, there is one thing specific to GRUB. Namely, how to specify a -configuration file in a BOOTP/DHCP server. For now, GRUB uses the tag -@samp{150}, to get the name of a configuration file. The following is an -example with a BOOTP configuration: - -@example -@group -.allhost:hd=/tmp:bf=null:\ - :ds=145.71.35.1 145.71.32.1:\ - :sm=255.255.254.0:\ - :gw=145.71.35.1:\ - :sa=145.71.35.5: - -foo:ht=1:ha=63655d0334a7:ip=145.71.35.127:\ - :bf=/nbgrub:\ - :tc=.allhost:\ - :T150="(nd)/tftpboot/menu.lst.foo": -@end group -@end example - -Note that you should specify the drive name @code{(nd)} in the name of -the configuration file. This is because you might change the root drive -before downloading the configuration from the TFTP server when the -preset menu feature is used (@pxref{Preset Menu}). - -See the manual of your BOOTP/DHCP server for more information. The -exact syntax should differ a little from the example. - - @node Serial terminal @chapter Using GRUB via a serial line @@ -1581,214 +748,6 @@ GRUB provides you with an alternative menu interface, because the normal menu requires several fancy features of your terminal. -@node Preset Menu -@chapter Embedding a configuration file into GRUB - -GRUB supports a @dfn{preset menu} which is to be always loaded before -starting. The preset menu feature is useful, for example, when your -computer has no console but a serial cable. In this case, it is -critical to set up the serial terminal as soon as possible, since you -cannot see any message until the serial terminal begins to work. So it -is good to run the commands @command{serial} (@pxref{serial}) and -@command{terminal} (@pxref{terminal}) before anything else at the -start-up time. - -How the preset menu works is slightly complicated: - -@enumerate -@item -GRUB checks if the preset menu feature is used, and loads the preset -menu, if available. This includes running commands and reading boot -entries, like an ordinary configuration file. - -@item -GRUB checks if the configuration file is available. Note that this check -is performed @strong{regardless of the existence of the preset -menu}. The configuration file is loaded even if the preset menu was -loaded. - -@item -If the preset menu includes any boot entries, they are cleared when -the configuration file is loaded. It doesn't matter whether the -configuration file has any entries or no entry. The boot entries in the -preset menu are used only when GRUB fails in loading the configuration -file. -@end enumerate - -To enable the preset menu feature, you must rebuild GRUB specifying a -file to the configure script with the option -@option{--enable-preset-menu}. The file has the same semantics as -normal configuration files (@pxref{Configuration}). - -Another point you should take care is that the diskless support -(@pxref{Diskless}) diverts the preset menu. Diskless images embed a -preset menu to execute the command @command{bootp} (@pxref{bootp}) -automatically, unless you specify your own preset menu to the configure -script. This means that you must put commands to initialize a network in -the preset menu yourself, because diskless images don't set it up -implicitly, when you use the preset menu explicitly. - -Therefore, a typical preset menu used with diskless support would be -like this: - -@example -@group -# Set up the serial terminal, first of all. -serial --unit=0 --speed=19200 -terminal --timeout=0 serial - -# Initialize the network. -dhcp -@end group -@end example - - -@node Security -@chapter Protecting your computer from cracking - -You may be interested in how to prevent ordinary users from doing -whatever they like, if you share your computer with other people. So -this chapter describes how to improve the security of GRUB. - -One thing which could be a security hole is that the user can do too -many things with GRUB, because GRUB allows one to modify its configuration -and run arbitrary commands at run-time. For example, the user can even -read @file{/etc/passwd} in the command-line interface by the command -@command{cat} (@pxref{cat}). So it is necessary to disable all the -interactive operations. - -Thus, GRUB provides a @dfn{password} feature, so that only administrators -can start the interactive operations (i.e. editing menu entries and -entering the command-line interface). To use this feature, you need to -run the command @command{password} in your configuration file -(@pxref{password}), like this: - -@example -password --md5 PASSWORD -@end example - -If this is specified, GRUB disallows any interactive control, until you -press the key @key{p} and enter a correct password. The option -@option{--md5} tells GRUB that @samp{PASSWORD} is in MD5 format. If it -is omitted, GRUB assumes the @samp{PASSWORD} is in clear text. - -You can encrypt your password with the command @command{md5crypt} -(@pxref{md5crypt}). For example, run the grub shell (@pxref{Invoking the -grub shell}), and enter your password: - -@example -@group -grub> md5crypt -Password: ********** -Encrypted: $1$U$JK7xFegdxWH6VuppCUSIb. -@end group -@end example - -Then, cut and paste the encrypted password to your configuration file. - -Also, you can specify an optional argument to @command{password}. See -this example: - -@example -password PASSWORD /boot/grub/menu-admin.lst -@end example - -In this case, GRUB will load @file{/boot/grub/menu-admin.lst} as a -configuration file when you enter the valid password. - -Another thing which may be dangerous is that any user can choose any -menu entry. Usually, this wouldn't be problematic, but you might want to -permit only administrators to run some of your menu entries, such as an -entry for booting an insecure OS like DOS. - -GRUB provides the command @command{lock} (@pxref{lock}). This command -always fails until you enter the valid password, so you can use it, like -this: - -@example -@group -title Boot DOS -lock -rootnoverify (hd0,1) -makeactive -chainload +1 -@end group -@end example - -You should insert @command{lock} right after @command{title}, because -any user can execute commands in an entry until GRUB encounters -@command{lock}. - -You can also use the command @command{password} instead of -@command{lock}. In this case the boot process will ask for the password -and stop if it was entered incorrectly. Since the @command{password} -takes its own @var{PASSWORD} argument this is useful if you want -different passwords for different entries. - - -@node Images -@chapter GRUB image files - -GRUB consists of several images: two essential stages, optional stages -called @dfn{Stage 1.5}, one image for bootable CD-ROM, and two network -boot images. Here is a short overview of them. @xref{Internals}, for -more details. - -@table @file -@item stage1 -This is an essential image used for booting up GRUB. Usually, this is -embedded in an MBR or the boot sector of a partition. Because a PC boot -sector is 512 bytes, the size of this image is exactly 512 bytes. - -All @file{stage1} must do is to load Stage 2 or Stage 1.5 from a local -disk. Because of the size restriction, @file{stage1} encodes the -location of Stage 2 (or Stage 1.5) in a block list format, so it never -understand any filesystem structure. - -@item stage2 -This is the core image of GRUB. It does everything but booting up -itself. Usually, this is put in a filesystem, but that is not required. - -@item e2fs_stage1_5 -@itemx fat_stage1_5 -@itemx ffs_stage1_5 -@itemx jfs_stage1_5 -@itemx minix_stage1_5 -@itemx reiserfs_stage1_5 -@itemx vstafs_stage1_5 -@itemx xfs_stage1_5 - -These are called @dfn{Stage 1.5}, because they serve as a bridge -between @file{stage1} and @file{stage2}, that is to say, Stage 1.5 is -loaded by Stage 1 and Stage 1.5 loads Stage 2. The difference between -@file{stage1} and @file{*_stage1_5} is that the former doesn't -understand any filesystem while the latter understands one filesystem -(e.g. @file{e2fs_stage1_5} understands ext2fs). So you can move the -Stage 2 image to another location safely, even after GRUB has been -installed. - -While Stage 2 cannot generally be embedded in a fixed area as the size -is so large, Stage 1.5 can be installed into the area right after an MBR, -or the boot loader area of a ReiserFS or a FFS. - -@item stage2_eltorito -This is a boot image for CD-ROMs using the @dfn{no emulation mode} in -El Torito specification. This is identical to Stage 2, except that -this boots up without Stage 1 and sets up a special drive @samp{(cd)}. - -@item nbgrub -This is a network boot image for the Network Image Proposal used by some -network boot loaders, such as Etherboot. This is mostly the same as -Stage 2, but it also sets up a network and loads a configuration file -from the network. - -@item pxegrub -This is another network boot image for the Preboot Execution Environment -used by several Netboot ROMs. This is identical to @file{nbgrub}, except -for the format. -@end table - - @node Filesystem @chapter Filesystem syntax and semantics @@ -1907,8 +866,6 @@ the command-line interface. @menu * Command-line interface:: The flexible command-line interface * Menu interface:: The simple menu interface -* Menu entry editor:: Editing a menu entry -* Hidden menu interface:: The hidden menu interface @end menu @@ -2029,19 +986,6 @@ does not support @dfn{undo}, you can do almost the same thing by just returning to the main menu. -@node Hidden menu interface -@section The hidden menu interface - -When your terminal is dumb or you request GRUB to hide the menu -interface explicitly with the command @command{hiddenmenu} -(@pxref{hiddenmenu}), GRUB doesn't show the menu interface (@pxref{Menu -interface}) and automatically boots the default entry, unless -interrupted by pressing @key{ESC}. - -When you interrupt the timeout and your terminal is dumb, GRUB falls -back to the command-line interface (@pxref{Command-line interface}). - - @node Commands @chapter The list of available commands @@ -2094,64 +1038,12 @@ start, where they are ignored. These commands can only be used in the menu: @menu -* default:: Set the default entry -* fallback:: Set the fallback entry -* hiddenmenu:: Hide the menu interface -* timeout:: Set the timeout -* title:: Start a menu entry +* menuentry:: Start a menu entry @end menu -@node default -@subsection default - -@deffn Command default num -Set the default entry to the entry number @var{num}. Numbering starts -from 0, and the entry number 0 is the default if the command is not -used. - -You can specify @samp{saved} instead of a number. In this case, the -default entry is the entry saved with the command -@command{savedefault}. @xref{savedefault}, for more information. -@end deffn - - -@node fallback -@subsection fallback - -@deffn Command fallback num... -Go into unattended boot mode: if the default boot entry has any errors, -instead of waiting for the user to do something, immediately start -over using the @var{num} entry (same numbering as the @code{default} -command (@pxref{default})). This obviously won't help if the machine was -rebooted by a kernel that GRUB loaded. You can specify multiple -fallback entry numbers. -@end deffn - - -@node hiddenmenu -@subsection hiddenmenu - -@deffn Command hiddenmenu -Don't display the menu. If the command is used, no menu will be -displayed on the control terminal, and the default entry will be -booted after the timeout expired. The user can still request the -menu to be displayed by pressing @key{ESC} before the timeout -expires. See also @ref{Hidden menu interface}. -@end deffn - - -@node timeout -@subsection timeout - -@deffn Command timeout sec -Set a timeout, in @var{sec} seconds, before automatically booting the -default entry (normally the first entry defined). -@end deffn - - -@node title -@subsection title +@node menuentry +@subsection menuentry @deffn Command title name @dots{} Start a new boot entry, and set its name to the contents of the rest of @@ -2165,242 +1057,11 @@ the line, starting with the first non-space character. Commands usable anywhere in the menu and in the command-line. @menu -* bootp:: Initialize a network device via BOOTP -* color:: Color the menu interface -* device:: Specify a file as a drive -* dhcp:: Initialize a network device via DHCP -* hide:: Hide a partition -* ifconfig:: Configure a network device manually -* pager:: Change the state of the internal pager -* partnew:: Make a primary partition -* parttype:: Change the type of a partition -* password:: Set a password for the menu interface -* rarp:: Initialize a network device via RARP * serial:: Set up a serial device -* setkey:: Configure the key map -* terminal:: Choose a terminal * terminfo:: Define escape sequences for a terminal -* tftpserver:: Specify a TFTP server -* unhide:: Unhide a partition @end menu -@node bootp -@subsection bootp - -@deffn Command bootp [@option{--with-configfile}] -Initialize a network device via the @dfn{BOOTP} protocol. This command -is only available if GRUB is compiled with netboot support. See also -@ref{Network}. - -If you specify @option{--with-configfile} to this command, GRUB will -fetch and load a configuration file specified by your BOOTP server -with the vendor tag @samp{150}. -@end deffn - - -@node color -@subsection color - -@deffn Command color normal [highlight] -Change the menu colors. The color @var{normal} is used for most -lines in the menu (@pxref{Menu interface}), and the color -@var{highlight} is used to highlight the line where the cursor -points. If you omit @var{highlight}, then the inverted color of -@var{normal} is used for the highlighted line. The format of a color is -@code{@var{foreground}/@var{background}}. @var{foreground} and -@var{background} are symbolic color names. A symbolic color name must be -one of these: - -@itemize @bullet -@item -black - -@item -blue - -@item -green - -@item -cyan - -@item -red - -@item -magenta - -@item -brown - -@item -light-gray - -@strong{These below can be specified only for the foreground.} - -@item -dark-gray - -@item -light-blue - -@item -light-green - -@item -light-cyan - -@item -light-red - -@item -light-magenta - -@item -yellow - -@item -white -@end itemize - -But only the first eight names can be used for @var{background}. You can -prefix @code{blink-} to @var{foreground} if you want a blinking -foreground color. - -This command can be used in the configuration file and on the command -line, so you may write something like this in your configuration file: - -@example -@group -# Set default colors. -color light-gray/blue black/light-gray - -# Change the colors. -title OS-BS like -color magenta/blue black/magenta -@end group -@end example -@end deffn - - -@node device -@subsection device - -@deffn Command device drive file -In the grub shell, specify the file @var{file} as the actual drive for a -@sc{bios} drive @var{drive}. You can use this command to create a disk -image, and/or to fix the drives guessed by GRUB when GRUB fails to -determine them correctly, like this: - -@example -@group -grub> @kbd{device (fd0) /floppy-image} -grub> @kbd{device (hd0) /dev/sd0} -@end group -@end example - -This command can be used only in the grub shell (@pxref{Invoking the -grub shell}). -@end deffn - - -@node dhcp -@subsection dhcp - -@deffn Command dhcp [--with-configfile] -Initialize a network device via the @dfn{DHCP} protocol. Currently, -this command is just an alias for @command{bootp}, since the two -protocols are very similar. This command is only available if GRUB is -compiled with netboot support. See also @ref{Network}. - -If you specify @option{--with-configfile} to this command, GRUB will -fetch and load a configuration file specified by your DHCP server -with the vendor tag @samp{150}. -@end deffn - - -@node hide -@subsection hide - -@deffn Command hide partition -Hide the partition @var{partition} by setting the @dfn{hidden} bit in -its partition type code. This is useful only when booting DOS or Windows -and multiple primary FAT partitions exist in one disk. See also -@ref{DOS/Windows}. -@end deffn - - -@node ifconfig -@subsection ifconfig - -@deffn Command ifconfig [@option{--server=server}] [@option{--gateway=gateway}] [@option{--mask=mask}] [@option{--address=address}] -Configure the IP address, the netmask, the gateway, and the server -address of a network device manually. The values must be in dotted -decimal format, like @samp{192.168.11.178}. The order of the options is -not important. This command shows current network configuration, if no -option is specified. See also @ref{Network}. -@end deffn - - -@node pager -@subsection pager - -@deffn Command pager [flag] -Toggle or set the state of the internal pager. If @var{flag} is -@samp{on}, the internal pager is enabled. If @var{flag} is @samp{off}, -it is disabled. If no argument is given, the state is toggled. -@end deffn - - -@node partnew -@subsection partnew - -@deffn Command partnew part type from len -Create a new primary partition. @var{part} is a partition specification -in GRUB syntax (@pxref{Naming convention}); @var{type} is the partition -type and must be a number in the range @code{0-0xff}; @var{from} is -the starting address and @var{len} is the length, both in sector units. -@end deffn - - -@node parttype -@subsection parttype - -@deffn Command parttype part type -Change the type of an existing partition. @var{part} is a partition -specification in GRUB syntax (@pxref{Naming convention}); @var{type} -is the new partition type and must be a number in the range 0-0xff. -@end deffn - - -@node password -@subsection password - -@deffn Command password [@option{--md5}] passwd [new-config-file] -If used in the first section of a menu file, disable all interactive -editing control (menu entry editor and command-line) and entries -protected by the command @command{lock}. If the password @var{passwd} is -entered, it loads the @var{new-config-file} as a new config file and -restarts the GRUB Stage 2, if @var{new-config-file} is -specified. Otherwise, GRUB will just unlock the privileged instructions. -You can also use this command in the script section, in which case it -will ask for the password, before continuing. The option -@option{--md5} tells GRUB that @var{passwd} is encrypted with -@command{md5crypt} (@pxref{md5crypt}). -@end deffn - - -@node rarp -@subsection rarp - -@deffn Command rarp -Initialize a network device via the @dfn{RARP} protocol. This command -is only available if GRUB is compiled with netboot support. See also -@ref{Network}. -@end deffn - - @node serial @subsection serial @@ -2426,169 +1087,6 @@ support. See also @ref{Serial terminal}. @end deffn -@node setkey -@subsection setkey - -@deffn Command setkey [to_key from_key] -Change the keyboard map. The key @var{from_key} is mapped to the key -@var{to_key}. If no argument is specified, reset key mappings. Note that -this command @emph{does not} exchange the keys. If you want to exchange -the keys, run this command again with the arguments exchanged, like this: - -@example -grub> @kbd{setkey capslock control} -grub> @kbd{setkey control capslock} -@end example - -A key must be an alphabet letter, a digit, or one of these symbols: -@samp{escape}, @samp{exclam}, @samp{at}, @samp{numbersign}, -@samp{dollar}, @samp{percent}, @samp{caret}, @samp{ampersand}, -@samp{asterisk}, @samp{parenleft}, @samp{parenright}, @samp{minus}, -@samp{underscore}, @samp{equal}, @samp{plus}, @samp{backspace}, -@samp{tab}, @samp{bracketleft}, @samp{braceleft}, @samp{bracketright}, -@samp{braceright}, @samp{enter}, @samp{control}, @samp{semicolon}, -@samp{colon}, @samp{quote}, @samp{doublequote}, @samp{backquote}, -@samp{tilde}, @samp{shift}, @samp{backslash}, @samp{bar}, @samp{comma}, -@samp{less}, @samp{period}, @samp{greater}, @samp{slash}, -@samp{question}, @samp{alt}, @samp{space}, @samp{capslock}, @samp{FX} -(@samp{X} is a digit), and @samp{delete}. This table describes to which -character each of the symbols corresponds: - -@table @samp -@item exclam -@samp{!} - -@item at -@samp{@@} - -@item numbersign -@samp{#} - -@item dollar -@samp{$} - -@item percent -@samp{%} - -@item caret -@samp{^} - -@item ampersand -@samp{&} - -@item asterisk -@samp{*} - -@item parenleft -@samp{(} - -@item parenright -@samp{)} - -@item minus -@samp{-} - -@item underscore -@samp{_} - -@item equal -@samp{=} - -@item plus -@samp{+} - -@item bracketleft -@samp{[} - -@item braceleft -@samp{@{} - -@item bracketright -@samp{]} - -@item braceright -@samp{@}} - -@item semicolon -@samp{;} - -@item colon -@samp{:} - -@item quote -@samp{'} - -@item doublequote -@samp{"} - -@item backquote -@samp{`} - -@item tilde -@samp{~} - -@item backslash -@samp{\} - -@item bar -@samp{|} - -@item comma -@samp{,} - -@item less -@samp{<} - -@item period -@samp{.} - -@item greater -@samp{>} - -@item slash -@samp{/} - -@item question -@samp{?} - -@item space -@samp{ } -@end table -@end deffn - - -@node terminal -@subsection terminal - -@deffn Command terminal [@option{--dumb}] [@option{--no-echo}] [@option{--no-edit}] [@option{--timeout=secs}] [@option{--lines=lines}] [@option{--silent}] [@option{console}] [@option{serial}] [@option{hercules}] -Select a terminal for user interaction. The terminal is assumed to be -VT100-compatible unless @option{--dumb} is specified. If both -@option{console} and @option{serial} are specified, then GRUB will use -the one where a key is entered first or the first when the timeout -expires. If neither are specified, the current setting is -reported. This command is only available if GRUB is compiled with serial -support. See also @ref{Serial terminal}. - -This may not make sense for most users, but GRUB supports Hercules -console as well. Hercules console is usable like the ordinary console, -and the usage is quite similar to that for serial terminals: specify -@option{hercules} as the argument. - -The option @option{--lines} defines the number of lines in your -terminal, and it is used for the internal pager function. If you don't -specify this option, the number is assumed as 24. - -The option @option{--silent} suppresses the message to prompt you to -hit any key. This might be useful if your system has no terminal -device. - -The option @option{--no-echo} has GRUB not to echo back input -characters. This implies the option @option{--no-edit}. - -The option @option{--no-edit} disables the BASH-like editing feature. -@end deffn - - @node terminfo @subsection terminfo @@ -2604,31 +1102,6 @@ If no option is specified, the current settings are printed. @end deffn -@node tftpserver -@subsection tftpserver - -@deffn Command tftpserver ipaddr -@strong{Caution:} This command exists only for backward -compatibility. Use @command{ifconfig} (@pxref{ifconfig}) instead. - -Override a TFTP server address returned by a BOOTP/DHCP/RARP server. The -argument @var{ipaddr} must be in dotted decimal format, like -@samp{192.168.0.15}. This command is only available if GRUB is compiled -with netboot support. See also @ref{Network}. -@end deffn - - -@node unhide -@subsection unhide - -@deffn Command unhide partition -Unhide the partition @var{partition} by clearing the @dfn{hidden} bit in -its partition type code. This is useful only when booting DOS or Windows -and multiple primary partitions exist on one disk. See also -@ref{DOS/Windows}. -@end deffn - - @node Command-line and menu entry commands @section The list of command-line and menu entry commands @@ -2637,56 +1110,17 @@ you forget a command, you can run the command @command{help} (@pxref{help}). @menu -* blocklist:: Get the block list notation of a file * boot:: Start up your operating system * cat:: Show the contents of a file * chainloader:: Chain-load another boot loader * cmp:: Compare two files * configfile:: Load a configuration file -* debug:: Toggle the debug flag -* displayapm:: Display APM information -* displaymem:: Display memory configuration -* embed:: Embed Stage 1.5 -* find:: Find a file -* fstest:: Test a filesystem -* geometry:: Manipulate the geometry of a drive * halt:: Shut down your computer * help:: Show help messages -* impsprobe:: Probe SMP -* initrd:: Load an initrd -* install:: Install GRUB -* ioprobe:: Probe I/O ports used for a drive -* kernel:: Load a kernel -* lock:: Lock a menu entry -* makeactive:: Make a partition active -* map:: Map a drive to another -* md5crypt:: Encrypt a password in MD5 format -* module:: Load a module -* modulenounzip:: Load a module without decompression -* pause:: Wait for a key press -* quit:: Exit from the grub shell * reboot:: Reboot your computer -* read:: Read data from memory -* root:: Set GRUB's root device -* rootnoverify:: Set GRUB's root device without mounting -* savedefault:: Save current entry as the default entry -* setup:: Set up GRUB's installation automatically -* testload:: Load a file for testing a filesystem -* testvbe:: Test VESA BIOS EXTENSION -* uppermem:: Set the upper memory size -* vbeprobe:: Probe VESA BIOS EXTENSION @end menu -@node blocklist -@subsection blocklist - -@deffn Command blocklist file -Print the block list notation of the file @var{file}. @xref{Block list -syntax}. -@end deffn - - @node boot @subsection boot @@ -2753,93 +1187,6 @@ Load @var{file} as a configuration file. @end deffn -@node debug -@subsection debug - -@deffn Command debug -Toggle debug mode (by default it is off). When debug mode is on, some -extra messages are printed to show disk activity. This global debug flag -is mainly useful for GRUB developers when testing new code. -@end deffn - - -@node displayapm -@subsection displayapm - -@deffn Command displayapm -Display APM BIOS information. -@end deffn - - -@node displaymem -@subsection displaymem - -@deffn Command displaymem -Display what GRUB thinks the system address space map of the machine is, -including all regions of physical @sc{ram} installed. GRUB's -@dfn{upper/lower memory} display uses the standard BIOS interface for -the available memory in the first megabyte, or @dfn{lower memory}, and a -synthesized number from various BIOS interfaces of the memory starting -at 1MB and going up to the first chipset hole for @dfn{upper memory} -(the standard PC @dfn{upper memory} interface is limited to reporting a -maximum of 64MB). -@end deffn - - -@node embed -@subsection embed - -@deffn Command embed stage1_5 device -Embed the Stage 1.5 @var{stage1_5} in the sectors after the MBR if -@var{device} is a drive, or in the @dfn{boot loader} area if @var{device} -is a FFS partition or a ReiserFS partition.@footnote{The latter feature -has not been implemented yet.} Print the number of sectors which -@var{stage1_5} occupies, if successful. - -Usually, you don't need to run this command directly. @xref{setup}. -@end deffn - - -@node find -@subsection find - -@deffn Command find filename -Search for the file name @var{filename} in all mountable partitions -and print the list of the devices which contain the file. The file -name @var{filename} should be an absolute file name like -@code{/boot/grub/stage1}. -@end deffn - - -@node fstest -@subsection fstest - -@deffn Command fstest -Toggle filesystem test mode. -Filesystem test mode, when turned on, prints out data corresponding to -all the device reads and what values are being sent to the low-level -routines. The format is @samp{<@var{partition-offset-sector}, -@var{byte-offset}, @var{byte-length}>} for high-level reads inside a -partition, and @samp{[@var{disk-offset-sector}]} for low-level sector -requests from the disk. -Filesystem test mode is turned off by any use of the @command{install} -(@pxref{install}) or @command{testload} (@pxref{testload}) commands. -@end deffn - - -@node geometry -@subsection geometry - -@deffn Command geometry drive [cylinder head sector [total_sector]] -Print the information for the drive @var{drive}. In the grub shell, you -can set the geometry of the drive arbitrarily. The number of -cylinders, the number of heads, the number of sectors and the number of -total sectors are set to CYLINDER, HEAD, SECTOR and TOTAL_SECTOR, -respectively. If you omit TOTAL_SECTOR, then it will be calculated -based on the C/H/S values automatically. -@end deffn - - @node halt @subsection halt @@ -2865,220 +1212,6 @@ about each of the commands which match those @var{patterns}. @end deffn -@node impsprobe -@subsection impsprobe - -@deffn Command impsprobe -Probe the Intel Multiprocessor Specification 1.1 or 1.4 configuration -table and boot the various CPUs which are found into a tight loop. This -command can be used only in the Stage 2, but not in the grub shell. -@end deffn - - -@node initrd -@subsection initrd - -@deffn Command initrd file @dots{} -Load an initial ramdisk for a Linux format boot image and set the -appropriate parameters in the Linux setup area in memory. See also -@ref{GNU/Linux}. -@end deffn - - -@node install -@subsection install - -@deffn Command install [@option{--force-lba}] [@option{--stage2=os_stage2_file}] stage1_file [@option{d}] dest_dev stage2_file [addr] [@option{p}] [config_file] [real_config_file] -This command is fairly complex, and you should not use this command -unless you are familiar with GRUB. Use @command{setup} (@pxref{setup}) -instead. - -In short, it will perform a full install presuming the Stage 2 or Stage -1.5@footnote{They're loaded the same way, so we will refer to the Stage -1.5 as a Stage 2 from now on.} is in its final install location. - -In slightly more detail, it will load @var{stage1_file}, validate that -it is a GRUB Stage 1 of the right version number, install in it a -blocklist for loading @var{stage2_file} as a Stage 2. If the option -@option{d} is present, the Stage 1 will always look for the actual -disk @var{stage2_file} was installed on, rather than using the booting -drive. The Stage 2 will be loaded at address @var{addr}, which must be -@samp{0x8000} for a true Stage 2, and @samp{0x2000} for a Stage 1.5. If -@var{addr} is not present, GRUB will determine the address -automatically. It then writes the completed Stage 1 to the first block -of the device @var{dest_dev}. If the options @option{p} or -@var{config_file} are present, then it reads the first block of stage2, -modifies it with the values of the partition @var{stage2_file} was found -on (for @option{p}) or places the string @var{config_file} into the area -telling the stage2 where to look for a configuration file at boot -time. Likewise, if @var{real_config_file} is present and -@var{stage2_file} is a Stage 1.5, then the Stage 2 @var{config_file} is -patched with the configuration file name @var{real_config_file}. This -command preserves the DOS BPB (and for hard disks, the partition table) -of the sector the Stage 1 is to be installed into. - -@strong{Caution:} Several buggy BIOSes don't pass a booting drive -properly when booting from a hard disk drive. Therefore, you will -unfortunately have to specify the option @option{d}, whether your -Stage2 resides at the booting drive or not, if you have such a -BIOS. We know these are defective in this way: - -@table @asis -@item -Fujitsu LifeBook 400 BIOS version 31J0103A - -@item -HP Vectra XU 6/200 BIOS version GG.06.11 -@end table - -@strong{Caution2:} A number of BIOSes don't return a correct LBA support -bitmap even if they do have the support. So GRUB provides a solution to -ignore the wrong bitmap, that is, the option @option{--force-lba}. Don't -use this option if you know that your BIOS doesn't have LBA support. - -@strong{Caution3:} You must specify the option @option{--stage2} in the -grub shell, if you cannot unmount the filesystem where your stage2 file -resides. The argument should be the file name in your operating system. -@end deffn - - -@node ioprobe -@subsection ioprobe - -@deffn Command ioprobe drive -Probe I/O ports used for the drive @var{drive}. This command will list -the I/O ports on the screen. For technical information, -@xref{Internals}. -@end deffn - - -@node kernel -@subsection kernel - -@deffn Command kernel [@option{--type=type}] [@option{--no-mem-option}] file @dots{} -Attempt to load the primary boot image (Multiboot a.out or @sc{elf}, -Linux zImage or bzImage, FreeBSD a.out, NetBSD a.out, etc.) from -@var{file}. The rest of the line is passed verbatim as the @dfn{kernel -command-line}. Any modules must be reloaded after using this command. - -This command also accepts the option @option{--type} so that you can -specify the kernel type of @var{file} explicitly. The argument -@var{type} must be one of these: @samp{netbsd}, @samp{freebsd}, -@samp{openbsd}, @samp{linux}, @samp{biglinux}, and -@samp{multiboot}. However, you need to specify it only if you want to -load a NetBSD @sc{elf} kernel, because GRUB can automatically determine -a kernel type in the other cases, quite safely. - -The option @option{--no-mem-option} is effective only for Linux. If the -option is specified, GRUB doesn't pass the option @option{mem=} to the -kernel. This option is implied for Linux kernels 2.4.18 and newer. -@end deffn - - -@node lock -@subsection lock - -@deffn Command lock -Prevent normal users from executing arbitrary menu entries. You must use -the command @command{password} if you really want this command to be -useful (@pxref{password}). - -This command is used in a menu, as shown in this example: - -@example -@group -title This entry is too dangerous to be executed by normal users -lock -root (hd0,a) -kernel /no-security-os -@end group -@end example - -See also @ref{Security}. -@end deffn - - -@node makeactive -@subsection makeactive - -@deffn Command makeactive -Set the active partition on the root disk to GRUB's root device. -This command is limited to @emph{primary} PC partitions on a hard disk. -@end deffn - - -@node map -@subsection map - -@deffn Command map to_drive from_drive -Map the drive @var{from_drive} to the drive @var{to_drive}. This is -necessary when you chain-load some operating systems, such as DOS, if -such an OS resides at a non-first drive. Here is an example: - -@example -@group -grub> @kbd{map (hd0) (hd1)} -grub> @kbd{map (hd1) (hd0)} -@end group -@end example - -The example exchanges the order between the first hard disk and the -second hard disk. See also @ref{DOS/Windows}. -@end deffn - - -@node md5crypt -@subsection md5crypt - -@deffn Command md5crypt -Prompt to enter a password, and encrypt it in MD5 format. The encrypted -password can be used with the command @command{password} -(@pxref{password}). See also @ref{Security}. -@end deffn - - -@node module -@subsection module - -@deffn Command module file @dots{} -Load a boot module @var{file} for a Multiboot format boot image (no -interpretation of the file contents are made, so the user of this -command must know what the kernel in question expects). The rest of the -line is passed as the @dfn{module command-line}, like the -@command{kernel} command. You must load a Multiboot kernel image before -loading any module. See also @ref{modulenounzip}. -@end deffn - - -@node modulenounzip -@subsection modulenounzip - -@deffn Command modulenounzip file @dots{} -The same as @command{module} (@pxref{module}), except that automatic -decompression is disabled. -@end deffn - - -@node pause -@subsection pause - -@deffn Command pause message @dots{} -Print the @var{message}, then wait until a key is pressed. Note that -placing @key{^G} (ASCII code 7) in the message will cause the speaker to -emit the standard beep sound, which is useful when prompting the user to -change floppies. -@end deffn - - -@node quit -@subsection quit - -@deffn Command quit -Exit from the grub shell @command{grub} (@pxref{Invoking the grub -shell}). This command can be used only in the grub shell. -@end deffn - - @node reboot @subsection reboot @@ -3087,551 +1220,6 @@ Reboot the computer. @end deffn -@node read -@subsection read - -@deffn Command read addr -Read a 32-bit value from memory at address @var{addr} and display it in -hex format. -@end deffn - - -@node root -@subsection root - -@deffn Command root device [hdbias] -Set the current @dfn{root device} to the device @var{device}, then -attempt to mount it to get the partition size (for passing the partition -descriptor in @code{ES:ESI}, used by some chain-loaded boot loaders), the -BSD drive-type (for booting BSD kernels using their native boot format), -and correctly determine the PC partition where a BSD sub-partition is -located. The optional @var{hdbias} parameter is a number to tell a BSD -kernel how many BIOS drive numbers are on controllers before the current -one. For example, if there is an IDE disk and a SCSI disk, and your -FreeBSD root partition is on the SCSI disk, then use a @samp{1} for -@var{hdbias}. - -See also @ref{rootnoverify}. -@end deffn - - -@node rootnoverify -@subsection rootnoverify - -@deffn Command rootnoverify device [hdbias] -Similar to @command{root} (@pxref{root}), but don't attempt to mount the -partition. This is useful for when an OS is outside of the area of the -disk that GRUB can read, but setting the correct root device is still -desired. Note that the items mentioned in @command{root} above which -derived from attempting the mount will @emph{not} work correctly. -@end deffn - - -@node savedefault -@subsection savedefault - -@deffn Command savedefault num -Save the current menu entry or @var{num} if specified as a default -entry. Here is an example: - -@example -@group -default saved -timeout 10 - -title GNU/Linux -root (hd0,0) -kernel /boot/vmlinuz root=/dev/sda1 vga=ext -initrd /boot/initrd -savedefault - -title FreeBSD -root (hd0,a) -kernel /boot/loader -savedefault -@end group -@end example - -With this configuration, GRUB will choose the entry booted previously as -the default entry. - -You can specify @samp{fallback} instead of a number. Then, next -fallback entry is saved. Next fallback entry is chosen from fallback -entries. Normally, this will be the first entry in fallback ones. - -See also @ref{default} and @ref{Invoking grub-set-default}. -@end deffn - - -@node setup -@subsection setup - -@deffn Command setup [@option{--force-lba}] [@option{--stage2=os_stage2_file}] [@option{--prefix=dir}] install_device [image_device] -Set up the installation of GRUB automatically. This command uses the -more flexible command @command{install} (@pxref{install}) in the backend -and installs GRUB into the device @var{install_device}. If -@var{image_device} is specified, then find the GRUB images -(@pxref{Images}) in the device @var{image_device}, otherwise use the -current @dfn{root device}, which can be set by the command -@command{root}. If @var{install_device} is a hard disk, then embed a -Stage 1.5 in the disk if possible. - -The option @option{--prefix} specifies the directory under which GRUB -images are put. If it is not specified, GRUB automatically searches them -in @file{/boot/grub} and @file{/grub}. - -The options @option{--force-lba} and @option{--stage2} are just passed -to @command{install} if specified. @xref{install}, for more -information. -@end deffn - - -@node testload -@subsection testload - -@deffn Command testload file -Read the entire contents of @var{file} in several different ways and -compare them, to test the filesystem code. The output is somewhat -cryptic, but if no errors are reported and the final @samp{i=@var{X}, -filepos=@var{Y}} reading has @var{X} and @var{Y} equal, then it is -definitely consistent, and very likely works correctly subject to a -consistent offset error. If this test succeeds, then a good next step is -to try loading a kernel. -@end deffn - - -@node testvbe -@subsection testvbe - -@deffn Command testvbe mode -Test the VESA BIOS EXTENSION mode @var{mode}. This command will switch -your video card to the graphics mode, and show an endless animation. Hit -any key to return. See also @ref{vbeprobe}. -@end deffn - - -@node uppermem -@subsection uppermem - -@deffn Command uppermem kbytes -Force GRUB to assume that only @var{kbytes} kilobytes of upper memory -are installed. Any system address range maps are discarded. - -@strong{Caution:} This should be used with great caution, and should -only be necessary on some old machines. GRUB's BIOS probe can pick up -all @sc{ram} on all new machines the author has ever heard of. It can -also be used for debugging purposes to lie to an OS. -@end deffn - - -@node vbeprobe -@subsection vbeprobe - -@deffn Command vbeprobe [mode] -Probe VESA BIOS EXTENSION information. If the mode @var{mode} is -specified, show only the information about @var{mode}. Otherwise, this -command lists up available VBE modes on the screen. See also -@ref{testvbe}. -@end deffn - - -@node Troubleshooting -@chapter Error messages reported by GRUB - -This chapter describes error messages reported by GRUB when you -encounter trouble. @xref{Invoking the grub shell}, if your problem is -specific to the grub shell. - -@menu -* Stage1 errors:: Errors reported by the Stage 1 -* Stage1.5 errors:: Errors reported by the Stage 1.5 -* Stage2 errors:: Errors reported by the Stage 2 -@end menu - - -@node Stage1 errors -@section Errors reported by the Stage 1 - -The general way that the Stage 1 handles errors is to print an error -string and then halt. Pressing @kbd{@key{CTRL}-@key{ALT}-@key{DEL}} will -reboot. - -The following is a comprehensive list of error messages for the Stage 1: - -@table @asis -@item Hard Disk Error -The stage2 or stage1.5 is being read from a hard disk, and the attempt -to determine the size and geometry of the hard disk failed. - -@item Floppy Error -The stage2 or stage1.5 is being read from a floppy disk, and the attempt -to determine the size and geometry of the floppy disk failed. It's listed -as a separate error since the probe sequence is different than for hard -disks. - -@item Read Error -A disk read error happened while trying to read the stage2 or stage1.5. - -@item Geom Error -The location of the stage2 or stage1.5 is not in the portion of the disk -supported directly by the BIOS read calls. This could occur because the -BIOS translated geometry has been changed by the user or the disk is -moved to another machine or controller after installation, or GRUB was -not installed using itself (if it was, the Stage 2 version of this error -would have been seen during that process and it would not have completed -the install). -@end table - - -@node Stage1.5 errors -@section Errors reported by the Stage 1.5 - -The general way that the Stage 1.5 handles errors is to print an error -number in the form @code{Error @var{num}} and then halt. Pressing -@kbd{@key{CTRL}-@key{ALT}-@key{DEL}} will reboot. - -The error numbers correspond to the errors reported by Stage -2. @xref{Stage2 errors}. - - -@node Stage2 errors -@section Errors reported by the Stage 2 - -The general way that the Stage 2 handles errors is to abort the -operation in question, print an error string, then (if possible) either -continue based on the fact that an error occurred or wait for the user to -deal with the error. - -The following is a comprehensive list of error messages for the Stage 2 -(error numbers for the Stage 1.5 are listed before the colon in each -description): - -@table @asis -@item 1 : Filename must be either an absolute filename or blocklist -This error is returned if a file name is requested which doesn't fit the -syntax/rules listed in the @ref{Filesystem}. - -@item 2 : Bad file or directory type -This error is returned if a file requested is not a regular file, but -something like a symbolic link, directory, or FIFO. - -@item 3 : Bad or corrupt data while decompressing file -This error is returned if the run-length decompression code gets an -internal error. This is usually from a corrupt file. - -@item 4 : Bad or incompatible header in compressed file -This error is returned if the file header for a supposedly compressed -file is bad. - -@item 5 : Partition table invalid or corrupt -This error is returned if the sanity checks on the integrity of the -partition table fail. This is a bad sign. - -@item 6 : Mismatched or corrupt version of stage1/stage2 -This error is returned if the install command points to incompatible -or corrupt versions of the stage1 or stage2. It can't detect corruption -in general, but this is a sanity check on the version numbers, which -should be correct. - -@item 7 : Loading below 1MB is not supported -This error is returned if the lowest address in a kernel is below the -1MB boundary. The Linux zImage format is a special case and can be -handled since it has a fixed loading address and maximum size. - -@item 8 : Kernel must be loaded before booting -This error is returned if GRUB is told to execute the boot sequence -without having a kernel to start. - -@item 9 : Unknown boot failure -This error is returned if the boot attempt did not succeed for reasons -which are unknown. - -@item 10 : Unsupported Multiboot features requested -This error is returned when the Multiboot features word in the Multiboot -header requires a feature that is not recognized. The point of this is -that the kernel requires special handling which GRUB is probably -unable to provide. - -@item 11 : Unrecognized device string -This error is returned if a device string was expected, and the string -encountered didn't fit the syntax/rules listed in the @ref{Filesystem}. - -@item 12 : Invalid device requested -This error is returned if a device string is recognizable but does not -fall under the other device errors. - -@item 13 : Invalid or unsupported executable format -This error is returned if the kernel image being loaded is not -recognized as Multiboot or one of the supported native formats (Linux -zImage or bzImage, FreeBSD, or NetBSD). - -@item 14 : Filesystem compatibility error, cannot read whole file -Some of the filesystem reading code in GRUB has limits on the length of -the files it can read. This error is returned when the user runs into -such a limit. - -@item 15 : File not found -This error is returned if the specified file name cannot be found, but -everything else (like the disk/partition info) is OK. - -@item 16 : Inconsistent filesystem structure -This error is returned by the filesystem code to denote an internal -error caused by the sanity checks of the filesystem structure on disk -not matching what it expects. This is usually caused by a corrupt -filesystem or bugs in the code handling it in GRUB. - -@item 17 : Cannot mount selected partition -This error is returned if the partition requested exists, but the -filesystem type cannot be recognized by GRUB. - -@item 18 : Selected cylinder exceeds maximum supported by BIOS -This error is returned when a read is attempted at a linear block -address beyond the end of the BIOS translated area. This generally -happens if your disk is larger than the BIOS can handle (512MB for -(E)IDE disks on older machines or larger than 8GB in general). - -@item 19 : Linux kernel must be loaded before initrd -This error is returned if the initrd command is used before loading a -Linux kernel. - -@item 20 : Multiboot kernel must be loaded before modules -This error is returned if the module load command is used before loading -a Multiboot kernel. It only makes sense in this case anyway, as GRUB has -no idea how to communicate the presence of such modules to a -non-Multiboot-aware kernel. - -@item 21 : Selected disk does not exist -This error is returned if the device part of a device- or full file name -refers to a disk or BIOS device that is not present or not recognized by -the BIOS in the system. - -@item 22 : No such partition -This error is returned if a partition is requested in the device part of -a device- or full file name which isn't on the selected disk. - -@item 23 : Error while parsing number -This error is returned if GRUB was expecting to read a number and -encountered bad data. - -@item 24 : Attempt to access block outside partition -This error is returned if a linear block address is outside of the disk -partition. This generally happens because of a corrupt filesystem on the -disk or a bug in the code handling it in GRUB (it's a great debugging -tool). - -@item 25 : Disk read error -This error is returned if there is a disk read error when trying to -probe or read data from a particular disk. - -@item 26 : Too many symbolic links -This error is returned if the link count is beyond the maximum -(currently 5), possibly the symbolic links are looped. - -@item 27 : Unrecognized command -This error is returned if an unrecognized command is entered on the -command-line or in a boot sequence section of a configuration file and -that entry is selected. - -@item 28 : Selected item cannot fit into memory -This error is returned if a kernel, module, or raw file load command is -either trying to load its data such that it won't fit into memory or it -is simply too big. - -@item 29 : Disk write error -This error is returned if there is a disk write error when trying to -write to a particular disk. This would generally only occur during an -install of set active partition command. - -@item 30 : Invalid argument -This error is returned if an argument specified to a command is invalid. - -@item 31 : File is not sector aligned -This error may occur only when you access a ReiserFS partition by -block-lists (e.g. the command @command{install}). In this case, you -should mount the partition with the @samp{-o notail} option. - -@item 32 : Must be authenticated -This error is returned if you try to run a locked entry. You should -enter a correct password before running such an entry. - -@item 33 : Serial device not configured -This error is returned if you try to change your terminal to a serial -one before initializing any serial device. - -@item 34 : No spare sectors on the disk -This error is returned if a disk doesn't have enough spare space. This -happens when you try to embed Stage 1.5 into the unused sectors after -the MBR, but the first partition starts right after the MBR or they are -used by EZ-BIOS. -@end table - - -@node Invoking the grub shell -@chapter Invoking the grub shell - -This chapter documents the grub shell @command{grub}. Note that the grub -shell is an emulator; it doesn't run under the native environment, so it -sometimes does something wrong. Therefore, you shouldn't trust it too -much. If there is anything wrong with it, don't hesitate to try the -native GRUB environment, especially when it guesses a wrong map between -BIOS drives and OS devices. - -@menu -* Basic usage:: How to use the grub shell -* Installation under UNIX:: How to install GRUB via @command{grub} -* Device map:: The map between BIOS drives and OS devices -@end menu - - -@node Basic usage -@section Introduction into the grub shell - -You can use the command @command{grub} for installing GRUB under your -operating systems and for a testbed when you add a new feature into GRUB -or when fixing a bug. @command{grub} is almost the same as the Stage 2, -and, in fact, it shares the source code with the Stage 2 and you can use -the same commands (@pxref{Commands}) in @command{grub}. It is emulated by -replacing BIOS calls with UNIX system calls and libc functions. - -The command @command{grub} accepts the following options: - -@table @option -@item --help -Print a summary of the command-line options and exit. - -@item --version -Print the version number of GRUB and exit. - -@item --verbose -Print some verbose messages for debugging purpose. - -@item --device-map=@var{file} -Use the device map file @var{file}. The format is described in -@ref{Device map}. - -@item --no-floppy -Do not probe any floppy drive. This option has no effect if the option -@option{--device-map} is specified (@pxref{Device map}). - -@item --probe-second-floppy -Probe the second floppy drive. If this option is not specified, the grub -shell does not probe it, as that sometimes takes a long time. If you -specify the device map file (@pxref{Device map}), the grub shell just -ignores this option. - -@item --config-file=@var{file} -Read the configuration file @var{file} instead of -@file{/boot/grub/menu.lst}. The format is the same as the normal GRUB -syntax. See @ref{Filesystem}, for more information. - -@item --boot-drive=@var{drive} -Set the stage2 @var{boot_drive} to @var{drive}. This argument should be -an integer (decimal, octal or hexadecimal). - -@item --install-partition=@var{par} -Set the stage2 @var{install_partition} to @var{par}. This argument -should be an integer (decimal, octal or hexadecimal). - -@item --no-config-file -Do not use the configuration file even if it can be read. - -@item --no-curses -Do not use the screen handling interface by the curses even if it is -available. - -@item --batch -This option has the same meaning as @samp{--no-config-file --no-curses}. - -@item --read-only -Disable writing to any disk. - -@item --hold -Wait until a debugger will attach. This option is useful when you want -to debug the startup code. -@end table - - -@node Installation under UNIX -@section How to install GRUB via @command{grub} - -The installation procedure is the same as under the @dfn{native} Stage -2. @xref{Installation}, for more information. The command -@command{grub}-specific information is described here. - -What you should be careful about is @dfn{buffer cache}. @command{grub} -makes use of raw devices instead of filesystems that your operating -systems serve, so there exists a potential problem that some cache -inconsistency may corrupt your filesystems. What we recommend is: - -@itemize @bullet -@item -If you can unmount drives to which GRUB may write any amount of data, -unmount them before running @command{grub}. - -@item -If a drive cannot be unmounted but can be mounted with the read-only -flag, mount it in read-only mode. That should be secure. - -@item -If a drive must be mounted with the read-write flag, make sure that no -activity is being done on it while the command @command{grub} is -running. - -@item -Reboot your operating system as soon as possible. This is probably not -required if you follow the rules above, but reboot is the most secure -way. -@end itemize - -In addition, enter the command @command{quit} when you finish the -installation. That is @emph{very important} because @command{quit} makes -the buffer cache consistent. Do not push @key{C-c}. - -If you want to install GRUB non-interactively, specify @samp{--batch} -option in the command-line. This is a simple example: - -@example -@group -#!/bin/sh - -# Use /usr/sbin/grub if you are on an older system. -/sbin/grub --batch </dev/null 2>/dev/null -root (hd0,0) -setup (hd0) -quit -EOT -@end group -@end example - - -@node Device map -@section The map between BIOS drives and OS devices - -When you specify the option @option{--device-map} (@pxref{Basic usage}), -the grub shell creates the @dfn{device map file} automatically unless it -already exists. The file name @file{/boot/grub/device.map} is preferred. - -If the device map file exists, the grub shell reads it to map BIOS -drives to OS devices. This file consists of lines like this: - -@example -@var{device} @var{file} -@end example - -@var{device} is a drive specified in the GRUB syntax (@pxref{Device -syntax}), and @var{file} is an OS file, which is normally a device -file. - -The reason why the grub shell gives you the device map file is that it -cannot guess the map between BIOS drives and OS devices correctly in -some environments. For example, if you exchange the boot sequence -between IDE and SCSI in your BIOS, it gets the order wrong. - -Thus, edit the file if the grub shell makes a mistake. You can put any -comments in the file if needed, as the grub shell assumes that a line is -just a comment if the first character is @samp{#}. - - @node Invoking grub-install @chapter Invoking grub-install @@ -3655,11 +1243,6 @@ Print a summary of the command-line options and exit. @item --version Print the version number of GRUB and exit. -@item --force-lba -Force GRUB to use LBA mode even for a buggy BIOS. Use this option only -if your BIOS doesn't work properly in LBA mode even though it supports -LBA mode. - @item --root-directory=@var{dir} Install GRUB images under the directory @var{dir} instead of the root directory. This option is useful when you want to install GRUB into a @@ -3671,14 +1254,6 @@ you have a separate @dfn{boot} partition which is mounted on @kbd{grub-install --root-directory=/boot hd0} @end example -@item --grub-shell=@var{file} -Use @var{file} as the grub shell. You can append arbitrary options to -@var{file} after the file name, like this: - -@example -@kbd{grub-install --grub-shell="grub --read-only" /dev/fd0} -@end example - @item --recheck Recheck the device map, even if @file{/boot/grub/device.map} already exists. You should use this option whenever you add/remove a disk @@ -3686,137 +1261,6 @@ into/from your computer. @end table -@node Invoking grub-md5-crypt -@chapter Invoking grub-md5-crypt - -The program @command{grub-md5-crypt} encrypts a password in MD5 format. -This is just a frontend of the grub shell (@pxref{Invoking the grub -shell}). Passwords encrypted by this program can be used with the -command @command{password} (@pxref{password}). - -@command{grub-md5-crypt} accepts the following options: - -@table @option -@item --help -Print a summary of the command-line options and exit. - -@item --version -Print the version information and exit. - -@item --grub-shell=@var{file} -Use @var{file} as the grub shell. -@end table - - -@node Invoking grub-terminfo -@chapter Invoking grub-terminfo - -The program @command{grub-terminfo} generates a terminfo command from -a terminfo name (@pxref{terminfo}). The result can be used in the -configuration file, to define escape sequences. Because GRUB assumes -that your terminal is vt100-compatible by default, this would be -useful only if your terminal is uncommon (such as vt52). - -@command{grub-terminfo} accepts the following options: - -@table @option -@item --help -Print a summary of the command-line options and exit. - -@item --version -Print the version information and exit. -@end table - -You must specify one argument to this command. For example: - -@example -@kbd{grub-terminfo vt52} -@end example - - -@node Invoking grub-set-default -@chapter Invoking grub-set-default - -The program @command{grub-set-default} sets the default boot entry for -GRUB. This automatically creates a file named @file{default} under -your GRUB directory (i.e. @file{/boot/grub}), if it is not -present. This file is used to determine the default boot entry when -GRUB boots up your system when you use @samp{default saved} in your -configuration file (@pxref{default}), and to save next default boot -entry when you use @samp{savedefault} in a boot entry -(@pxref{savedefault}). - -@command{grub-set-default} accepts the following options: - -@table @option -@item --help -Print a summary of the command-line options and exit. - -@item --version -Print the version information and exit. - -@item --root-directory=@var{dir} -Use the directory @var{dir} instead of the root directory -(i.e. @file{/}) to define the location of the default file. This -is useful when you mount a disk which is used for another system. -@end table - -You must specify a single argument to @command{grub-set-default}. This -argument is normally the number of a default boot entry. For example, -if you have this configuration file: - -@example -@group -default saved -timeout 10 - -title GNU/Hurd -root (hd0,0) -... - -title GNU/Linux -root (hd0,1) -... -@end group -@end example - -and if you want to set the next default boot entry to GNU/Linux, you -may execute this command: - -@example -@kbd{grub-set-default 1} -@end example - -Because the entry for GNU/Linux is @samp{1}. Note that entries are -counted from zero. So, if you want to specify GNU/Hurd here, then you -should specify @samp{0}. - -This feature is very useful if you want to test a new kernel or to -make your system quite robust. @xref{Making your system robust}, for -more hints about how to set up a robust system. - - -@node Invoking mbchk -@chapter Invoking mbchk - -The program @command{mbchk} checks for the format of a Multiboot -kernel. We recommend using this program before booting your own kernel -by GRUB. - -@command{mbchk} accepts the following options: - -@table @option -@item --help -Print a summary of the command-line options and exit. - -@item --version -Print the version number of GRUB and exit. - -@item --quiet -Suppress all normal output. -@end table - - @node Obtaining and Building GRUB @appendix How to obtain and build GRUB