Ubuntu-gr Forum

ΚΟΜΜΑΤΙ 4(Το ανέλαβε ο c7p)

Κώδικας: Επιλογή όλων: [b]SECTION 4[/b] [b]Special Topics[/b] Installing GRUB 2 to your PC [b]grub-install The most useful command[/b] The various types of command modes. "c," grub>, Konsole BASH, edit "e", emu, TAB Completion How to get information about your drives and devices Key commands: At Konsole : sudo fdisk -lu At the GRUB 2 prompt: grub> ls Boot menu: Adding or removing an OS entry Boot menu: Create a custom boot entry Boot menu: Making your own custom grub.cfg 4 ways to boot an OS: configfile, symlinks, direct booting, chainloader [b]Dedicated GRUB 2 partition[/b]: How to build it [b]GRUB 2 Flashdrive:[/b] How to build it Use of the term "root" GRUB's Root Device, the Linux statement, root=UUID=, --root-directory=DIR INSTALL_DEVICE Dual booting: How to set it up <-- put this at the end of Section 4 Cheat sheet: [b]GRUB 2 Practical Reminders[/b]: listing of key files, commands, methods [b]Installing GRUB 2 To Your PC[/b] To install GRUB 2 to your PC so it boots your PC into your OSs, two steps are required. 1 You need to get the GRUB 2 files installed to your PC, somewhere in the Kubuntu filesystem. 2 Then use those GRUB 2 files to install GRUB 2 to your PC's drives or devices so it can serve as a bootloader to boot your PC into your Kubuntu and your other OSs. Step 1: [b]Get the GRUB 2 files[/b] Install the GRUB 2 package in your Kubuntu OS using your package manager. Or, at Konsole, issue the following command: sudo apt-get install grub-pc Check it: Open your file manager (Konqueror or Dolphin or other), and see the GRUB 2 files under [b]/usr/lib/grub/i386-pc[/b] (called the GRUB 2 image directory, and contains a set of "master" GRUB files). Step 2: [b]Install the GRUB 2 files so they serve as a bootloader[/b] Suppose your first BIOS boot drive is sda (as seen in Kubuntu using at Konsole the command sudo fdisk -lu). Then, install GRUB 2 to the Master Boot Record of sda: sudo grub-install /dev/sda This also copies the GRUB 2 files into /boot/grub. Then to generate a fresh boot menu configuration file (/boot/grub/grub.cfg), run sudo update-grub or sudo grub-mkconfig [u]More Details About This[/u] CAUTION, fair warning: [u]Have a bootable Super Grub Disk CD handy[/u] in case this messes up booting your PC. To install GRUB 2 files to your PC, open Konsole and run the commands sudo apt-get update sudo apt-cache search grub-pc (returns: grub-pc - GRand Unified Bootloader, version 2 (PC/BIOS version)) sudo apt-get install grub-pc Then, install GRUB 2 to the Master Boot Record of your first BIOS boot drive. For example, if that MBR is sda, the command would be sudo grub-install /dev/sda And then update grub.cfg: sudo update-grub (or sudo grub-mkconfig) Reboot to see what happens. The old GRUB may also still be there (in which case you saw an entry on the boot menu to chainload into GRUB 2), in which case you may run sudo update-from-grub-legacy to replace GRUB Legacy with GRUB 2 IF YOU WISH TO DO SO. [u]Troubleshooting[/u] Installing GRUB 2 to the MBR: using [b][u]--recheck[/u][/b] Example sudo grub-install /dev/sda grub-probe: error: cannot find a GRUB drive for /dev/sda. Auto-detection of a filesystem module failed. Please specify the module with the option `--modules' explicitly. So, try this: [b]sudo grub-install --recheck /dev/sda[/b] Installation finished. No error reported. This is the contents of the device map /boot/grub/device.map. Check if this is correct or not. If any of the lines is incorrect, fix it and re-run the script `grub-install'. (hd0) /dev/sda - - - - - [Start subsection] [b]grub-install The most useful command[/b] Full form: grub-install [OPTION] INSTALL_DEVICE Two very important options are --recheck Probe a device map even if it already exists --root-directory=DIR Install GRUB images under the directory DIR instead of the root directory (See discussion below.) Examples: INSTALL_DEVICE may be /dev/sda, /dev/sda1, hd0, hd1, etc. grub-install /dev/sda installs GRUB 2 to the MBR of drive sda. grub-install /dev/sda1 installs GRUB 2 to the boot sector of partition sda1. grub-install hd0 installs GRUB 2 to the MBR of drive hd0. grub-install --root-directory=/media/sdb1 /dev/sda sets up GRUB 2 files in the mounted partition /media/sdb1 and then installs GRUB 2 to the MBR of drive sda. (If there is no /boot/grub directory in sdb1, it will be created and filled with GRUB 2 files.) grub-install --recheck --root-directory=/media/sdb1 /dev/sda Do it again, and probe the /boot/grub/device.map (again). [u]Use the command sudo grub-install for these purposes[/u]: to refresh the entire GRUB 2 installation, or when you are re-installing GRUB 2 to fix a problem, or when you are installing GRUB 2 to another place or to a dedicated GRUB 2 partition or to a USB (flash) drive. A master script grub-install is a master script, called a utility, that invokes many other utilities (scripts) to help do its work. You issue this command at Konsole (Terminal) as root (using sudo). It does everything for you; it's a master fix-it-all command. Note: [b]/usr/lib/grub/i386-pc[/b] The master set of GRUB 2 files in your OS are kept in the GRUB 2 image directory /usr/lib/grub/i386-pc. They get there when you install GRUB 2 to your PC (or OS) using your package manager or using (sudo) apt-get install grub-pc. [u]grub-install does the following for you[/u]: > The command sudo grub-install copies the GRUB 2 files from /usr/lib/grub/i386-pc to the directory /boot/grub. If /boot/grub does not yet exist, it is created. > It probes your partition type and partitions (using grub-probe). > It builds a custom version of core.img for your setup, one of two very important files (along with boot.img). (In GRUB LEGACY terms,, boot.img corresponds to stage_1 and core.img to stage_2.) > Finally it installs GRUB 2 to your PC so it can boot some OS(s) for you. (It uses grub-setup to do this, setting boot.img in the MBR of your first BIOS boot drive and installs core.img either after the MBR or to a file system (e.g., your OS partition boot sector) See the note below for a few details.) [u]Two useful options[/u] --recheck Probe a device map even if it already exists --root-directory=DIR Install GRUB images under the directory DIR instead of the root directory --recheck If your grub-install command fails, complaining about a filesystem or not finding something, try it again with the option --recheck; like this example: sudo grub-install --recheck --root-directory=/media/sdb1 /dev/sda --root-directory=DIR Very useful. Instead of setting up your GRUB files in /boot/grub under the root directory of your OS, you can use this option to build a /boot/grub directory anywhere, and then use those GRUB 2 files to install GRUB 2 to a hard drive MBR, or to a partition boot sector, or elsewhere (e.g., USB drive or dedicated GRUB 2 partition). DIR is a directory, and so it is mounted. Thus, if using partition sdb1, for example, you must mount it, as say, /media/sdb1. [u]Dedicated GRUB 2 partition[/u] Suppose your OS is on some partition on one of your hard drives. And suppose you wish to build a dedicated GRUB 2 partition in sdb1, and that your first BIOS boot drive is sda, and that you wish to setup GRUB 2 files in sdb1 and use those to install GRUB to the MBR of sda. Here's the command: sudo grub-install --root-directory=/media/sdb1 /dev/sda Note that sdb1 is mounted as /media/sdb1; also that sda is specified as a device: /dev/sda (not just sda). See the subsection below titled "Dedicated GRUB 2 partition: How to build it" [u]USB flash drive[/u] Suppose your flash drive is seen in Kubuntu as /dev/sdc and it is mounted as /media/flashdrive. Then the command to setup and install GRUB 2 to it is: sudo grub-install --root-directory=/media/flashdrive /dev/sdc See the subsection below titled "GRUB 2 Flashdrive: How to build it" More details at: grub-install http://grub.enbug.org/FranklinPiat/grub-install.manpage grub-setup (You will probably never use this by itself; you will use grub-install and let it do the work for you.) http://grub.enbug.org/FranklinPiat/grub-setup.manpage NOTE: A few details about installing boot.img and core.img. GRUB Legacy uses stages: stage_1, stage_1.5, and stage_2. Those are replaced in GRUB 2 by [b]boot.img[/b] (a 512-byte file that corresponds to stage_1 and is installed to a MBR); there is no stage_1.5 in GRUB 2; and [b]core.img[/b] in GRUB 2 takes the place of stage_2 (or, perhaps, of both stage 1.5 and stage_2); it is built specific to your PC setup. The boot.img points at core.img; core.img is embedded in some fixed location (on a disk), but usually that location is in the same "cylinder" as the MBR that contains boot.img. (Details: the MBR goes into sector 1 and is 512 bytes, and that's where boot.img goes. This first cylinder has 63 sectors, so that leaves 62 sectors or 31,744 bytes (=62*512) where core.img may be embedded. This first cylinder (of 63 sectors containing boot.img and core.img) precedes the start of the first partition on that disk, which would start at sector 63 (counting of sectors starts at zero, so 63 sectors take us to the end of sector 62 = the start of sector 63). You will see this if you run as root fdisk -lu.) [End of subsection: grub-install The most useful command] - - - - - [b]The various types of command modes[/b] "c," grub>, Konsole BASH, edit "e", emu When working with GRUB, you must work with root privileges and so you must use sudo and kdesudo. For example, sudo grub-install /dev/sda, kdesudo konqueror, etc. The command modes you may use in GRUB 2 are the following. -- Konsole (BASH), in Kubuntu, at your regular prompt (as root), ~#: -- GRUB 2 emu (from Konsole, issue sudo grub-emu [OPTION]; this gives you a grub> prompt) =>TODO: More on this later. -- GRUB 2 command line interface (CLI), grub>. When you re-boot your PC, get the boot menu, and press the "c" key, you get a GRUB 2 prompt, grub>. That is the GRUB 2 CLI. You will also get grub> upon re-booting if you don't have a boot menu, grub.cfg, or if your boot menu is broken. (See SECTION 3, the subsection titled "The GRUB prompt grub> -- What to do with it") -- Edit mode. Editing on the fly: when you re-boot and see your GRUB 2 boot menu, you can use the "e" key to edit your boot menu on a temporary basis (the edits are not permanent unless you later make them so). (See SECTION 3 -- Editing the boot menu during booting: "e" key.) => In all cases, help is nearby, and the commands are generally the same (or nearly so) in all modes, with a few differences. [u]Help[/u] Konsole BASH CLI: Appending --help to a command in CLI; for example sudo update-grub --help. GRUB CLI (grub>): At the GRUB 2 prompt simply type help and press Enter. To get help with a command, type help <command name>. Example: grub>help ls tells you about the command ls. Edit mode: The key tips are at the bottom of the screen after your press "e" to enter the edit mode from your on-screen boot menu. Also, at that point, you can press Control+c to get a grub>, then type help and/or use TAB completion. [b]TAB completion[/b] (grub>) While typing after the grub>, try pressing the TAB key and see what happens: in many cases, GRUB will try to help you complete the line with something meaningful or with choices. So type as much as you can recall or type a guess, then press TAB, then you may have to type another guess and press TAB again, and so on until you complete the line the way you want it. [b]GRUB 2 device numbering is different[/b] (hdx,y): hard drive x, partition y Hard drives start at zero (x=0), same as for GRUB Legacy. [b][u]Partitions start at 1[/u][/b] (y=1); in GRUB Legacy, partitions start at zero. [b]How to get information about your drives, devices, and files[/b] Key: at Konsole [b]sudo fdisk -lu[/b]; and [b]grub> ls[/b] We'll look at two cases: At the command line in Kubuntu (Konsole); and at the grub> prompt. [u]Konsole (BASH) command line[/u] [b]Exploring your hard drive(s):[/b] [b]sudo fdisk -lu[/b] => sudo fdisk -lu is [u]very useful, very important[/u]. GRUB version number: grub-install -v Drive space: df -h -T UUIDs (see NOTE below): blkid (or try sudo blkid); also: ls /dev/disk/by-uuid/ -alh grub.cfg, to see it: cat /boot/grub/grub.cfg fstab (filesystem table), to see it: cat /etc/fstab Mounting, how filesystems are mounted: cat /etc/mtab or: mount Boot directory /boot, to find it: df /boot Kernel version and gcc version (gcc=the GNU compiler used to build the kernel): cat /proc/version Kernel version: uname -r Linux version/name: lsb_release -a (hold the Shift key and the minus sign key to get _ . LSB = Linux Standard Base) KDE version (KDE=K Desktop Environment) for KDE 3.5: kde-config –version and for KDE 4: kde4-config --version NOTE: UUID = Universally Unique Identifier Starting with Kubuntu version 8.10, UUIDs are used to identify partitions. A UUID is a 16-byte number (= 128 bits). In canonical form, a UUID consists of 32 hexidecimal digits, displayed in 5 groups separated by hyphens. [u]At a GRUB prompt, grub>[/u] Exploring your hard drive(s): [b]grub> ls[/b] => [b]Very useful, very important.[/b] ([b]in GRUB Legacy, the geometry command is used instead of ls[/b]) [u]The ls command is very useful[/u] grub>ls gives you a list of your hard drives and partitions as GRUB sees them, in (hdx,y) GRUB 2 device notation. grub>ls / shows you the files under the current GRUB 2 root device. You can set that device using set root=. For example: grub>set root=(hd0,8) grub>ls / shows you all files under root. grub>ls /boot shows you all files--including kernels--under /boot. [u]UUIDs and filesystem type[/u] grub>ls (hd0,8) shows you information about the partition (hd0,8) including its filesystem type and its UUID. [u]The contents of a directory: grub>ls -l /directory[/u] Example grub>ls -l /boot shows you the kernel and initrd files. (The option -l indicates "long form" and gives more information. To see all files, including hidden files, use the option -a: grub>ls -a -l /boot; or grub>ls -al /boot) [u]GRUB 2 emulation sudo grub-emu[/u] At Konsole, to get a grub> prompt, type sudo grub-emu. To exit emu and return to Konsole, type halt. >>> [u]IMPORTANT[/u] [b]sudo grub-emu and then grub>ls[/b] While you are working at Konsole in Kubuntu, you may need to know how GRUB sees your drives and partitions, the (hdx,y)'s. You can switch into emulation made (sudo grub-emu)) and issue the list (ls) command at the GRUB prompt (grub>ls) to see your drives and GRUB devices. Type halt to return to BASH mode in Konsole. [u]Using search and cat[/u] GRUB files, what partitions they are in: grub>search /boot/grub/boot.img Boot menu, what partition(s) it is in: grub>search /boot/grub/grub.cfg Kernel, where it is: grub>search /vmlinuz Boot menu, to see it: grub>cat (hdx,y)/boot/grub/grub.cfg fstab, to see it: grub>cat (hdx,y)/etc/fstab Device.map, to see it: grub>cat (hdx,y)/boot/grub/device.map (NOTE: [b]In GRUB Legacy, the find command is used instead of search[/b].) [u]Restart (reboot), or shutdown (halt) your PC[/u] at a command line At Konsole: sudo shutdown -r now (re-boots the PC) sudo shutdown -h now (shuts down the PC) In GRUB: grub>reboot (re-boots the PC) grub>halt (shuts down the PC) [b]Boot menu: Adding or removing an OS entry to grub.cfg[/b] Rule: You do NOT edit grub.cfg directly. Instead, you work with script files in the folder /etc/grub.d. -- Linux operating systems, added automatically Look at your grub.cfg. The section ### BEGIN /etc/grub.d/10_linux ### ### END /etc/grub.d/10_linux ### contains Linux operating systems that were automatically detected by GRUB 2 using the script file /etc/grub.d/10_linux. Most of your Linux OSs should be detected this way and included in the boot menu grub.cfg. If not, you can create a custom boot entry (see below, "Boot menu: Create a custom boot entry"). -- Windows and other OSs added automatically This is done by the script /etc/grub.d/30_os-prober. -- Adding or removing OSs from your PC. After doing so, generate a new grub.cfg: sudo update-grub -- Add a boot menu entry by making your own[u] custom boot entry[/u], then run: sudo update-grub to generate a new grub.cfg. (See subsection below: "Boot menu: Create a custom boot entry") -- Removing a boot entry from grub.cfg: Two choices. (1) Simply remove the execute bit from the script file in /etc/grub.d that corresponds to (i.e., generates) the boot entry. Example: If that file is named 43_MyOS-1, then run the Konsole commands sudo chmod -x /etc/grub.d/43_MyOS-1 sudo update-grub (2) Or, remove the script file (for the boot entry) from the folder /etc/grub.d. Then run sudo update-grub to generate the new grub.cfg file. NOTE: If a custom file contains more than one boot entry, you may remove any number of them, leaving the rest. Then run sudo update-grub to generate your new boot menu, grub.cfg. [b]Boot menu: Custom boot entry[/b] This is easy, usually. -- There are 4 ways to make a boot entry (see "4 Ways To Boot an OS"). -- There is a custom template at /etc/grub.d/40_custom. -- After you write the script file for your custom boot entry, make it executable. -- Then generate a new grub.cfg by running sudo update-grub. See the subsection below: "4 Ways To Boot an OS." (direct booting, configfile, symlinks, chainload) Troubleshooting: Sometimes when you run grub-install or update-grub, it will fail to detect one of your OSs and excludes it from the boot menu grub.cfg. In that case, you could make a custom entry for it (as a script file in /etc/grub.d). [u]Direct booting[/u] To get a model for some of the entries, you have two choices: (1) Get it from your old boot menu (/boot/grub/menu.lst) from GRUB Legacy (if that is available on your PC). Or, it may also be here, made by GRUB 2: menu.lst_backup_by_grub2_postinst. (2) Go into the operating system itself (the one you wish to include), or perhaps access its filesystem using a live CD, and get the information from its own boot menu. [u]Example[/u] Making a custom entry for sidux. Method: Direct booting. It helps if you have a model for some of the entries. In the old boot menu (/boot/grub/menu.lst) from my GRUB Legacy, I had this boot entry for sidux: title Debian GNU/Linux, sidux kernel 2.6.28-5.slh.3-sidux-686 root (hd0,2) kernel /boot/vmlinuz-2.6.28-5.slh.3-sidux-686 root=UUID=306d94a5-107b-4c9e-ae03-a159e18dc1c7 ro quiet vga=791 initrd /boot/initrd.img-2.6.28-5.slh.3-sidux-686 Using a template (e.g., /etc/grub.d/40_custom), create an executable file for the sidux boot entry: Open an empty text document (as root) kdesudo kate Save the new file as, say, /etc/grub.d/41_sidux_sda3 Copy the kernel & initrd lines from menu.lst, change “kernel” to “linux,” adjust the sidux partition number to conform to GRUB 2 convention: Legacy GRUB: (hd0,2) GRUB 2: (hd0,3) Also, double check the UUID for sda3 by running sudo blkid. Result: The file /etc/grub.d/41_sidux_sda3 looks like this: #!/bin/sh echo "Adding sidux" >&2 cat << EOF menuentry "sidux on sda3" { set root=(hd0,3) linux /boot/vmlinuz-2.6.28-5.slh.3-sidux-686 root=UUID=306d94a5-107b-4c9e-ae03 a159e18dc1c7 ro quiet vga=791 initrd /boot/initrd.img-2.6.28-5.slh.3-sidux-686 } EOF The echo statement causes a line to be printed to the screen after executing sudo update-grub that says “sidux on sda3” so you can see it got done (i.e., that sidux got incorporated into the grub.cfg). Make the file executable (it is a script, a type of program): sudo chmod 744 /etc/grub.d/ 41_sidux_sda3 Or, sudo chmod +x /etc/grub.d/ 41_sidux_sda3 Or, in GUI, As root, open Konqueror (kdesudo konqueror), access /etc/grub.d, right click on 41_sidux_sda3, Properties, and check the “Executable” box; check Advanced Permission while you are at it. To incorporate the sidux file 41_sidux_sda3 as a boot entry in the boot menu configuration file /boot/grub/grub.cfg, run sudo update-grub Check that sidux is in your boot menu by opening /boot/grub/grub.cfg. [b]Boot menu: Making your own custom grub.cfg[/b] This is easy. (For another example, see the subsection below "Dedicated GRUB 2 partition: How to build it.") Taken directly from [u]drs305 excellent, detailed guide, GRUB 2 Basics[/u]: http://ubuntuforums.org/showthread.php?t=1195275 Building a Totally Customized Menu: Ok, admit you are a control freak and you want to see only what you build yourself - customized titles, no "memtest86+" and no extra kernels. Here is how you do it: -- Run sudo update-grub to get the current available kernels. -- Copy the desired "menuentry" listings from /boot/grub/grub.cfg to /etc/grub.d/40_custom The entry begins with the line starting with "menuentry" and ends with a line containing "}". -- Add any other "menuentry" items you wish to see on the boot menu. -- Edit the titles of the "menuentry" line if desired (between the quotation symbols). Do not change the lines following the "menuentry" line. Each entry should start with a "menuentry" line and end with a "}" on the last line. -- Remove the executable bit from /etc/grub.d/10_linux, /etc/grub.d/20_memtest86+ and /etc/grub.d/30_os-prober Removing the executable bit from any file in /etc/grub.d will exclude the file from being included in GRUB updates. To do it: sudo chmod -x /etc/grub.d/grub.d/10_linux /etc/grub.d/20_memtest86+ /etc/grub.d/30_os-prober -- Run "sudo update-grub" -- The updated /boot/grub/grub.cfg file should now contain only sections for "00_header", "05_debian_theme" and "40_custom". -- The grub.cfg file will not be updated with the addition of a new kernel. To add a new kernel, make "10_linux" executable, run "sudo update-grub" to refresh the available kernels, and repeat these instructions.

ΚΟΜΜΑΤΙ 5(Το ανέλαβε ο giormatsis)

Κώδικας: Επιλογή όλων: [b]4 Ways To Boot an OS[/b] configfile, symlinks, direct booting, chainloader You can use these methods -- in a boot menu -- at a grub> prompt (at the GRUB CLI) to boot OSs. If you use them at the GRUB CLI, you must type[u] the command boot[/u] at the end to make the methods symlinks, direct booting and chainloader work. You do not need the command boot in a configfile menu. You do not need the boot command in grub.cfg (it is implied there). NOTE: These are done the same as in GRUB Legacy but with a new format. But see the note on configfile below. NOTE: Each boot entry starts with a line menuentry "...some text..." { and ends with } >>> [u]Configfile booting[/u] This is easy and flexible; however, there's a [u]caveat:[/u] Both OSs must use the same version of GRUB--both the OS you are working in (where the boot menu is kept) and the OS you are booting. For example, consider these two statements in a menuentry: set root=(hd1,2) configfile /boot/grub/grub.cfg An equivalent way of doing it is this: configfile (hd1,2)/boot/grub/grub.cfg That tells your GRUB 2 to access partition (hd1,2), find the file /boot/grub/grub.cfg, show you that file so you can make a choice of which OS to boot, then boot the OS you choose. The GRUB doing the work is your native GRUB, the one you are using, not the GRUB in (hd1,2). Your native GRUB must be able to interpret the commands it finds in the grub.cfg of the OS you wish to boot. [u]When to avoid configfile[/u] When there is a mixture of GRUB versions on your PC, it is best to avoid using configfile. Instead, use chainloader or symlinks. Example (Taken from a grub.cfg. The # sign indicates a comment.) # Kubuntu 8.04.3 on sdb2, by configfile menuentry “Kubuntu 8.04.3 on sdb2, by configfile” { set root=(hd1,2) configfile /boot/grub/grub.cfg } >>> [u]Symlinks used in a boot entry[/u] Symlinks are like shortcuts, and they direct control from the link to the file they point at. Symlinks for the kernel and initrd files are already set up for you. Look for yourself. List all files (-a) in long or detailed form (-l) under your root partition (/) by issuing the following command at Konsole: ls -a -l / lrwxrwxrwx 1 root root 33 2009-08-02 11:01 initrd.img -> boot/initrd.img-2.6.24-24-generic lrwxrwxrwx 1 root root 33 2009-04-19 17:14 initrd.img.old -> boot/initrd.img-2.6.24-23-generic lrwxrwxrwx 1 root root 30 2009-08-02 11:01 vmlinuz -> boot/vmlinuz-2.6.24-2 4-generic lrwxrwxrwx 1 root root 30 2009-04-19 17:14 vmlinuz.old -> boot/vmlinuz-2.6.24-23-generic The symlink for the kernel is vmlinuz, and vmlinuz points at the NEWEST kernel. The symlink for the initrd is initrd.img, and initrd.img points at the NEWEST initrd. NOTE: The "l" at the left indicates "link." Note how the links point at their target files following the symbol ->. Note that the [u]symlinks are stored in your OS at the root level[/u]. NOTE: If you wish to [u]make a boot entry for the older kernel and initrd[/u], you must use the symlinks for them, [u]vmlinuz.old and initrd.img.old[/u]. If you use direct booting, you have to write out the exact kernel and initrd names: linux /boot/vmlinuz-2.6.24-24-generic root=UUID= vb687f89-ggjd-6ach-7755-77241i4b4fk3 ro quiet splash initrd /boot/initrd.img-2.6.24-24-generic With symlinks, vmlinuz starts at root and points at vmlinuz-2.6.24-24-generic and initrd.img starts at root and points at initrd.img-2.6.24-24-generic, so you can write more simply, linux /vmlinuz root=UUID= vb687f89-ggjd-6ach-7755-77241i4b4fk3 ro quiet splash initrd /initrd.img However, to simplify this when you are in an emergency trying to boot at the GRUB prompt (grub>), do it simply this way: Suppose this OS is Kubuntu 9.10 in (hd0,8) = sda8. Then you'd have menuentry “Kubuntu 9.10 on sda8, by symlinks” { set root=(hd0,8) linux /vmlinuz root=/dev/sda8 ro quiet splash initrd /initrd.img } or even simpler, when you can't remember the kernel options "ro quiet splash": menuentry “Kubuntu 9.10 on sda8, by symlinks” { set root=(hd0,8) linux /vmlinuz root=/dev/sda8 initrd /initrd.img } (ro = Read-Only and is the default. Thanks to dibl for this information.) [u]NOTE about the paths[/u] Notice the paths to the symlinks start at root / (since the symlinks are stored under root /); whereas the paths to the actual kernel & initrd files start at /boot (since the kernel and initrd are stored under /boot) Another Example # Kubuntu 9.10 on sdb7 symlinks, [u]normal mode[/u] menuentry “Kubuntu 9.10 on sdb7, by symlinks” { set root=(hd1,7) linux /vmlinuz root=/dev/sdb7 ro quiet splash initrd /initrd.img } This is normal mode. [u]If you want recovery mode[/u] (single user), replace the kernel options “ro quiet splash” with “ro single” (without quotes) >>> [u]Direct booting[/u] In direct booting, you use the actual kernel and initrd file names in the boot menuentry. NOTE If you use direct booting at the GRUB CLI, ie., at grub> prompt, you may use TAB completion to make your job easier. For example, grub>linux /boot/<Press TAB key now> and you will get some choices, such as vmlinuz-2.6.24-24-generic Example # Kubuntu 8.04 on sdb3, direct booting menuentry "Kubuntu 8.04 on sdb3, direct booting" { set root=(hd1,3) linux /boot/vmlinuz-2.6.24-24-generic root=UUID=db287e84-cbdd-4ca1-8745-85241a3b3fe2 ro quiet splash initrd /boot/initrd.img-2.6.24-24-generic } >>> [u]Chainloader booting[/u] When you boot an OS by chainloading, you use the chainloader command to pass control of the booting from your native GRUB to some other bootloader located in the MBR of a disk somewhere or in the boot sector of a partition. NOTE: For this to work, a bootloader must first be installed to the target MBR or boot sector. [u]A Linux example[/u] menuentry “Kubuntu 9.10 on sdb7, by chainloader” { set root=(hd1,7) chainloader +1 } "chainloader +1" says to go to sector 1 (of (hd1,7)) and turn control over to the bootloader found there. For this example to work, a bootloader (e.g., GRUB 2) must be installed to the partition (hd1,7). To install GRUB 2 to the boot sector of partition sdb7 (=(hd1,7)): sudo grub-install /dev/sdb7 This is another way to write the same boot entry: menuentry “Kubuntu 9.10 on sdb7, by chainloader” { chainloader (hd1,7)+1 } NOTE/Caveat? -- TODO -- Qqmike to check this. Herman says: If you're trying to chainload a partition boot sector, you might need to use the -f option, which tells GRUB to ignore the fact that there might not be a bootable disc signature there, (!= 0xaa55). I'm not sure about exactly when that's needed or isn't needed yet. It seems to be only needed in CLI Mode GRUB. Another Linux example menuentry “Drive sdc = hd2 by chainloader” { chainloader (hd2)+1 } If a bootloader (e.g., GRUB 2) has been installed to the Master Boot Record of drive sdc (= hd2), the menuentry will boot that hard drive by turning control over to the bootloader in its MBR. For this example to work, a bootloader (e.g., GRUB 2) must be installed to the Master Boot Record of drive sdc (= hd2). To install GRUB 2 to the Master Boot Record of drive sdc: sudo grub-install /dev/sdc Example Windows XP on sda1 menuentry “Windows XP on sda1, by chainloader” { set root=(hd0,1) chainloader +1 } [b]Dedicated GRUB 2 Partition: How To Build It[/b] Again, this is straightforward, much easier than in GRUB Legacy. 1 Create the GRUB 2 partition. Create a partition to be used as your dedicated GRUB 2 partition and format it. I use GParted Live CD to do this. At that time, you may if you wish, again using GParted, set a Label on your partition; e.g., “GRUB2” (without the quotation marks) (in GParted, use Partition > Labels). (Check the size of the /boot/grub folder to determine how big to make the partition. GRUB 2 files use just 572 KB (96 files, including 12 old ones) on my installation.) 2 Create grub.cfg. [u]In your home directory[/u], create a text file called grub.cfg and build your custom boot menu for the dedicated GRUB 2 partition. (For a sample, see below.) (To create the text file, two ways: (1) Right-click on your Desktop, Create New > Text File; or (2) open text editor Kate to an empty document by typing at Konsole kate and save it under the name grub.cfg in your home directory only! To do this as root, use kdesudo kate, but that is not necessary at this point.) [u]Caution:[/u] You may want to completely build your boot menu now and have it ready to go. To make your boot entries in your grub.cfg, see the subsection below "4 Ways To Boot an OS." 3 Install GRUB 2 to the MBR. From your Kubuntu OS, install GRUB 2 to the Master Boot Record (of your first BIOS boot drive) using GRUB 2 files set up in your dedicated GRUB 2 partition. Example Suppose sdb1 is your dedicated GRUB 2 partition, and assume it is mounted as /media/sdb1 (or, if you set the label GRUB2 on sdb1, this might be /media/GRUB2). And suppose you wish to install GRUB 2 to the MBR of sda which is set in BIOS to be your first boot drive. Do it this way: sudo grub-install –root-directory=/media/sdb1 /dev/sda See: http://grub.enbug.org/FranklinPiat/grub-install.manpage (That will also build the directory /boot/grub for you in your GRUB 2 partition.) 4 As root, copy your grub.cfg from your home directory to the GRUB 2 partition under the folder /boot/grub. (To do this in GUI, open your file manager as root and work from there; e.g., kdesudo konqueror or kdesudo dolphin.) 5 Set the boot flag on your dedicated GRUB 2 partition and re-boot to test it. Set the boot flag on the dedicated GRUB 2 partition: Do that using GParted either from your OS (K > System > Partition editor) or from the GParted Live CD. If you do it using the GParted Live CD, you might go this way now: After completing Step 4 (copying the grub.cfg file into the partition), put the GParted Live CD in the CD tray, let it be recognized, press Cancel, re-boot into GParted Live, set the boot flag on your dedicated GRUB 2 partition (Partition > Manage Flags), GParted > Quit, then double click GParted (large menu at top) to quit and re-boot, when prompted remove the GParted Live CD, and let the PC re-boot (and it will now be using your dedicated GRUB 2 partition), and see if it works. CAUTION: Remember to keep Super Grub Disk live CD handy. [u]IMPORTANT NOTE ABOUT KERNEL UPDATES[/u]: Using this method of building a dedicated GRUB 2 partition, YOU are in charge of the boot configuration file /boot/grub/grub.cfg that is located in the GRUB 2 partition. The stuff we talked about above--/etc/default/grub and the scripts /etc/grub.d and update-grub--does not apply. You must keep these two "shows" separate. [u]Edit the dedicated GRUB 2 file grub.cfg manually[/u]. If there ever is a problem, you may have to manually re-install GRUB 2 to the MBR (of the first BIOS boot drive) from the dedicated GRUB 2 partition. [u]Example[/u] Here's my dedicated GRUB 2 /boot/grub/grub.cfg: # # grub.cfg # This is my custom boot menu, called /boot/grub/grub.cfg, located in my dedicated Grub 2 partition sda1. # Set the timeout set timeout=10 # Set the default boot entry. set default=0 # Kubuntu 9.10 on sda8 by chainload menuentry "Kubuntu 9.10 on sda8, by chainload" { chainloader (hd0,8)+1 } # Kubuntu 9.10 on sda8 by configfile menuentry "Kubuntu 9.10 on sda8, by configfile" { configfile (hd0,8)/boot/grub/cfg } # Kubuntu 9.10 on sda8 by symlink menuentry "Kubuntu 9.10 on sda8, by symlink" { set root=(hd0,8) linux /vmlinuz root=/dev/sda8 ro quiet splash initrd /initrd.img } # Kubuntu 8.04.3 on sda2, by configfile menuentry "Kubuntu 8.04.3 on sda2, by configfile" { configfile (hd0,2)/boot/grub.cfg } # sidux on sda3, by direct booting menuentry "sidux on sda3" { set root=(hd0,3) linux /boot/vmlinuz-2.6.28-5.slh.3-sidux-686 root=UUID=306d94a5-107b-4c9e-ae03-a159e18dc1c7 ro quiet vga=791 initrd /boot/initrd.img-2.6.28-5.slh.3-sidux-686 } [b]GRUB 2 Flashdrive (USB flash drive)[/b] For the principles of installing GRUB 2, see the discussion under "Installing GRUB 2" and "The grub-install Command." [u]Example[/u] (My test of this.) I used a 1 GB Kingston, although the GRUB 2 files used just 51 MB. Partition and format the flash drive as ext2 (using GParted Partition Editor). (You could also use FAT32 or ext3 or some other filesystem.) Set the boot flag on the newly created partition (use GParted to do that: Partition > Manage Flags). Exit GParted. Unplug the flashdrive, then plug it in. In Kubuntu, to see how it is named, at Konsole run sudo fdisk -lu Output: Disk /dev/sdb: 1031 MB, 1031798784 bytes 255 heads, 63 sectors/track, 125 cylinders, total 2015232 sectors Units = sectors of 1 * 512 = 512 bytes Disk identifier: 0x000f0fe1 Device Boot Start End Blocks Id System /dev/sdb1 63 2008124 1004031 83 Linux Konqueror (or Dolphin) indicated it is mounted as /media/disk. => So it is seen as sdb with the partition sdb1 mounted as /media/disk. Install GRUB 2 to the flash drive. At Konsole: sudo grub-install --root-directory=/media/disk /dev/sdb Output: Installation finished. No error reported. This is the contents of the device map /media/disk/boot/grub/device.map. Check if this is correct or not. If any of the lines is incorrect, fix it and re-run the script `grub-install'. (hd0) /dev/sda (hd1) /dev/sdb (This is seen from Kubuntu's point of view now.) (This is the device.map on the flash drive, /boot/grub/device.map. I will ignore this! Doesn't matter too much. You could edit it as root to read (hd0) /dev/sda as seen from the point of view of the flash drive when it is used as a boot drive.) Let's move on, now ... Check to see that /boot/grub is created and filled with GRUB 2 files. [u]Reboot, setting BIOS to boot from the flash drive (USB booting)[/u]. The next thing I saw on the screen was: grub> I used the GRUB 2 command ls to see my drives and partitions (on the PC): grub>ls Since the PC booted from the flash drive, it was seen as hd0 with partition (hd0,1). (The drive that the PC actually boots from is always seen during its booting session as hd0--this is a general fact.) My regular HDD, normally seen as hd0 was now seen as hd1 and my Kubuntu 9.10 was in (hd1,8). So, to boot into Kubuntu, I did grub>chainloader (hd1,8)+1 grub>boot NOTE: Previously I had already installed GRUB 2 to the partition boot sector of Kubuntu in case I ever needed to chainload into it. (I used at Konsole in Kubuntu, sudo grub-install /dev/sda8, where sda8 is my Kubuntu partition when there is no other drive attached to the PC.) Had I not already done this, I could could NOT chainload into Kubuntu and would have to boot into Kubuntu in some other way, for example using symlinks: grub>ls would show me that Kubuntu is on (hd1,8) when booting from my GRUB 2 flash drive, and so to boot it, I'd do: grub>set root=(hd1,8) grub>linux /vmlinuz grub>initrd /initrd.img grub>boot Or, you could do this (if you remembered how!): grub>set root=(hd1,8) grub>linux /vmlinuz ro quite splash grub>initrd /initrd.img grub>boot Thus, I booted into Kubuntu using the GRUB 2 flash drive. Building a boot menu for the flash drive: You can create a text file /boot/grub/grub.cfg for the flash drive exactly as demonstrated under building a Dedicated GRUB 2 Partition. [u]Technical Note[/u]: To do so, you will probably have to work as root, say by opening Konqueror or Dolphin as root (kdesudo konqueror), or by opening Kate as root (kdesudo kate). However, you do not necessarily need a grub.cfg on the flash drive. You can simply use it as I did to explore your drives and then boot into an OS. If you do build a grub.cfg for it, you might include the OS(s) on your hard drive(s), and use the GRUB 2 flash drive to boot in emergencies, as you would use Super Grub Disk. Just remember that from the point of view of the grub.cfg on your flash drive, the other drives in your PC are shifted by 1 since upon booting the flash drive, it will be seen as hd0. If adrian15 builds Super Grub Disk for GRUB 2 and includes his usbshift function, then the story changes--for the principle of "USB drive shifting," see my how on building a GRUB flash drive: -- How To Make GRUB Thumb Drive http://kubuntuforums.net/forums/index.php?topic=3081748.0 [End of the flashdrive subsection] [b]Use of the Term "root"[/b] GRUB's Root Device, the Linux statement, root=UUID=, --root-directory=DIR INSTALL_DEVICE (To Do -- expand/clarify further) Example Consider this menuentry: ### BEGIN /etc/grub.d/10_Linux ### menuentry "Ubuntu 8.04.3 LTS, kernel 2.6.24-24-generic" { set root=(hd1,2) linux /boot/vmlinuz-2.6.24-24-generic root=UUID=0df17bc5-0056-4ef7-bfca-251194b6eb44 ro quiet splash initrd /boot/initrd.img-2.6.24-24-generic } The line set root=(hd1,2) sets the GRUB root device. The GRUB root device is the partition containing the kernel vmlinuz and initrd files. Thus, it is the partition containing the directory /boot. Also, since the GRUB boot files are contained in /boot/grub, the GRUB files are in that same /boot partition. Note this part of the linux line: root=UUID=0df17bc5-0056-4ef7-bfca-251194b6eb44. The UUID corresponds to the partition containing the root filesystem (/) of the OS (in this case, Ubuntu 8.04.3 LTS, kernel 2.6.24-24-generic) That partition (identified by its UUID) is passed to the Linux kernel using root=UUID=0df17bc5-0056-4ef7-bfca-251194b6eb44 in the linux line. So, the line "set root=(hd1,2)" is a message to GRUB 2; and "root=UUID=0df17bc5-0056-4ef7-bfca-251194b6eb44" is a message to the Linux kernel. Normally, for most users, the GRUB root partition (location of the kernel & initrd files) is the same as the root partition of the OS. In this case, the GRUB root device (partition) (hd1,2) would be the same as the root of the Kubuntu filesystem (and thus the UUID 0df17bc5-0056-4ef7-bfca-251194b6eb44 would be that of (hd1,2)). However, this need not be the case. If you have a separate /boot partition (separate from the root filesystem of the OS), then the set root=(hdx,y) statement and the root=UUID=xxx statement in the linux line will correspond to two different partitions. Another use of the word "root" and setting a "root" for GRUB occurs in the statement sudo grub-install --root-directory=DIR INSTALL_DEVICE; for example sudo grub-install --root-directory=/sdb1 sda where DIR is sdb1 and INSTALL_DEVICE is sda (i.e., the MBR of drive sda). This directs GRUB to install GRUB images to INSTALL_DEVICE (using the files in the GRUB image directory /usr/lib/grub/i386-pc/) under the directory DIR instead of the root directory (/) of the OS. [b]Dual booting: How To Set It Up[/b] This should follow the same guidelines as for GRUB Legacy, so see my GRUB Legacy how-to: How To GRUB Methods - Toolkit http://kubuntuforums.net/forums/index.php?topic=3081671.0 (See Sections 5 and 6) The differences will only involve how to edit things, especially the boot menu grub.cfg. As you know, in GRUB 2, you do NOT edit grub.cfg directly. Instead you edit the defaults file /etc/default/grub and the script files in /etc/grub.d following the present how-to you are reading now. [u]TO DO[/u]: More on this later. - - - - - - - - - - Cheat Sheet [b]GRUB 2 Practical Reminders[/b] -- for those who know what they are doing ;) [u]Files[/u] image: [b]/usr/lib/grub/i386-pc/[/b] boot/grub/grub.cfg Configuration file for the boot menu. Do NOT edit. /etc/default/grub Default settings file (Timeout, Default OS, kernel options) /etc/grub.d Folder of boot menu scripts: 00_header; 05_debian_theme: Background, text colors, themes 10_hurd Locates Hurd kernels; 10_linux Locates Linux kernels; 20_memtest86+ 30_os-prober: Searches for Linux and other OS's on all partitions 40_custom: Template for custom boot menu entries More: /boot/grub/device.map, [b]boot.img[/b] (MBR), [b]core.img[/b] [u]Fixing Things, Rescue[/u] Ctrl+Alt+Del reboot PC; Super Grub Disk New grub.cfg: [u]sudo update-grub[/u] or [u]sudo grub-mkconfig[/u] Install, re-install GRUB 2: [u]sudo grub-install [/u][INSTALL_DEVICE] to MBR: sudo grub-install /dev/sdx; partition: sudo grub-install /dev/sdxn [u]If error[/u]: grub-install [b]--recheck[/b] /dev/sdx; sudo grub-install --recheck /dev/sdxn Install GRUB 2 to MBR of sda using GRUB 2 in /dev/sdb1/boot/grub: sudo grub-install –root-directory=/media/sdb1 /dev/sda Install GRUB 2 to PC (/usr/lib/grub/i386-pc/): sudo apt-get install grub-pc [u]Live CD rescue: Re-install GRUB 2[/u] sudo mkdir /media/sda2 /media/dev sudo mount /dev/sda2 /media/sda2 sudo mount --bind /dev /media/dev Install GRUB 2 to MBR of sdb [or to partition sda2] using GRUB 2 files in sda2: sudo grub-install --root-directory=/media/sda2 /dev/sdb [or /dev/sda2] umount /media/sda2 /media/dev [u]Drives, partitions, information[/u] sudo fdisk -lu & grub>ls Naming: (hdx,y) or sdzy: drive x starts at 0; [u]partitions y start at 1[/u] Konsole: [b]sudo fdisk -lu[/b]; df -hT; mounting: cat /etc/mtab; or: mount UUIDs: sudo blkid; ls /dev/disk/by-uuid/ -alh Kernel ver: uname -r; cat /proc/version; Linux ver: lsb_release -a [b]sudo grub-emu and then grub>ls[/b] GRUB devices/drives: [b]grub>ls[/b]; grub>ls -al directory UUID of (hdx,y): grub>ls (hdx,y) Finding: grub>search /boot/grub/grub.cfg; grub>search /boot/grub/boot.img [u]Syntax, booting choices[/u] configfile: set root=(hdx,y) and configfile /boot/grub/grub.cfg; or: configfile (hdx,y)/boot/grub/grub.cfg symlinks: linux /vmlinuz root=UUID= xxx ro quiet splash; initrd /initrd.img symlinks: linux /vmlinuz root=/dev/sdxn ro quiet splash chainload: set root=(hdx,y) and chainloader +1; chainloader (hdx,y)+1 chainload a MBR: chainloader (hdx)+1 [u]Permissions[/u] Executable: sudo chmod 744 /etc/grub.d/[i]file[/i]; Remove: sudo chmod -x /etc/grub.d/[i]file[/i] Read only, everyone: sudo chmod 444 /etc/grub.d/[i]file[/i] GUI: kdesudo konqueror (dolphin), rt-click on [i]file,[/i] Properties, Permissions grub.cfg: sudo chmod +w /boot/grub/grub.cfg; sudo chmod -w /boot/grub/grub.cfg [u]Create a script[/u] called /etc/grub.d/NN_myscript Empty text doc: kdesudo kate; File > Save As /etc/grub.d/NN_myscript Type it (see template below). Make executable: sudo chmod 744 /etc/grub.d/NN_myscript or, sudo chmod +x /etc/grub.d/NN_myscript GUI: kdesudo konqueror (dolphin), rt-click, Properties, Permissions Make new grub.cfg: sudo update-grub, sudo grub-mkconfig > [u]Template,[/u] custom boot entry for file /etc/grub.d/NN_name #!/bin/sh echo "Adding name" >&2 cat << EOF menuentry "name of OS boot entry" { set root=(hdx,y) linux /boot/vmlinuz-xyz root=UUID=xxx initrd /boot/initrd.img-xyz } EOF [u]Edit a script[/u] GUI, kdesudo konqueror, rt-click on script file, Open With Kate/Kwrite. CLI, kdesudo kate /etc/grub.d/[i]script_name[/i] Edit the file, File>Save, Exit. New grub.cfg: sudo up-date grub; sudo grub-mkconfig [u]Flash drive[/u] /dev/sdc, sdc1 mounted at /media/disk; set boot flag; install GRUB 2: sudo grub-install --root-directory=/media/disk /dev/sdc [u]Separate GRUB 2 partition[/u]: mounted at /media/sdb1; sda=MBR of 1st BIOS drive sudo grub-install –root-directory=/media/sdb1 /dev/sda [u]Working as root[/u] (8.10+: kdesudo; 8.04: kdesu) kdesudo kate /path-to-file; kdesudo konqueror (or dolphin) Terminal as root: sudo –i; sudo su GUI file manager, navigate to file, right-click on file, Actions, Edit as Root. sudo [COMMAND]; sudo grub-install [INSTALL_DEVICE]; sudo update-grub; sudo grub-mkconfig [End of GRUB 2 Practical Reminders]

ΚΟΜΜΑΤΙ 6(Το ανέλαβε ο dimosfire)

Κώδικας: Επιλογή όλων: [b]SECTION 5[/b] [b]Tutorials: Where to go to study GRUB 2[/b] GRUB 2 Basics, by drs305 http://ubuntuforums.org/showthread.php?t=1195275 Absolutely excellent treatment of editing the boot menu and some basic key concepts of GRUB 2. GRUB 2 Manual http://grub.enbug.org/Manual We hope this will be all you need, along with the man pages. GNU GRUB 1.96/2 http://members.iinet.net/%7Eherman546/p20.html Looks like an encyclopedic, comprehensive coverage. Ubuntu versus Kubuntu tutorials: A GRUB 2 tutorial written for Ubuntu applies to Kubuntu. Watch for obvious differences in a few commands and OS tools. In Ubuntu you will see gksudo gedit /boot/grub/grub.cfg used for opening grub.cfg as root using text editor gedit. In Kubuntu, you would use kdesudo kate /boot/grub/grub.cfg. In Kubuntu, you will probably use Konqueror or Dolphin as your file manager. Also, there are different package managers used in each OS, even within the same OS at times! I think you'll be able to sort it out, and you can always post questions under one of the regular Kubuntu forums. >>> The GRUB commands are the same in both Ubuntu and Kubuntu and other Linus OSs. See also the [b]References[/b] which include both basic topics and advanced/special topics. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = [b]Appendix: Techniques[/b] --- Installing Kubuntu--GRUB 2 placement --- Working as root -- see below --- Permissions: read, write, execute; change the execute bit -- see below --- Chroot -- how to -- see below --- Konsole, see: Commands at Konsole: Beginners: 3 parts http://kubuntuforums.net/forums/index.php?topic=3091607.0 --- GRUB Legacy, see: How To GRUB Methods - Toolkit http://kubuntuforums.net/forums/index.php?topic=3081671.0 = = = = = = = = = = = = = = = = = = = = [b]Installing Kubuntu--GRUB 2 placement[/b] Live CD method The Live CD method of installing Kubuntu is easy, fast, and convenient because afterwards, you then have a Live CD to use for rescue and repair of your system. [u]Installing GRUB 2 files[/u] GRUB 2 is standard on Kubuntu starting with 9.10. During its installation from the Live CD, you can specify if you want GRUB 2installed, and if so, where to put it. Here's how: Start the Live CD installer. Step: Disk Setup "Specify Partitions Manually" Step: Summary Advanced button at lower right Check or un-check to install GRUB 2 bootloader Choose from the drop-down list where to install GRUB 2 sda = the MBR of drive sda sda1 = the first partition of drive sda sdb = the MBR of drive sdb etc. [u]Caution:[/u] > If you install GRUB to a MBR (sda, sdb, sdc, etc.), it will overwrite any other bootloader already installed to that MBR, and the GRUB 2 from the OS you are currently installing will then control the boot menu you see when you boot up your PC. That is OK, just so you know. > If you install GRUB 2 to the partition boot sector where you are currently installing the OS (e.g., sdan, for some n=1,2,3,4...), when you re-boot your PC, you will have to manually boot into your new OS you just installed. Do so using chainloader, as follows: -- Re-boot -- If you get some boot menu (from a prior Linux OS installation), press the "c" key to get a GRUB prompt, grub>. If you don't get a boot menu but only the GRUB prompt grub>, then that's OK, too. -- Let's say your new Kubuntu OS was installed to sda9. That is the same as (hd0,9). Then grub>chainloader (hd0,9)+1 grub>boot and you will boot into your new OS. [u]Building new boot menus[/u] > In your new OS, you can build a full boot menu simply by doing sudo update-grub or sudo grub-mkconfig. > In your existing OSs, you can re-build boot menus to include the new OS the same way: Konsole sudo update-grub or sudo grub-mkconfig > Worst case, if for some reason that doesn't work, you can make a custom boot entry to include your new OS. See SECTION 4. To get the details of the menuentry for the new OS for the existing grub.cfg, you might have to boot into the new OS and copy details from its grub.cfg. Or, simply boot your new OS using symlinks or chainloader (from another OS's boot menu), for which you do not need any details specific to the new OS. See SECTION 4, "4 Ways to boot an OS." = = = = = = = = = = = = = = = = = = = = [b]Working as root[/b] Opening a text editor (e.g., Kate, Kwrite, etc.) to see the file and/or to edit it: kdesudo kate path-to-file Example: kdesudo kate /etc/fstab Opening an empty text document as root: kdesudo kate (then File > Save As) Opening a file manager as root: in 8.10 and after: kdesudo konqueror (or dolphin) in 8.04: kdesu konqueror (dolphin) Opening a terminal as root: sudo –i (to get a “root” terminal) or: sudo su Your file manager may support this feature: Open the file manager, navigate to the file, right-click on the file, Actions, Edit as Root. At Konsole (BASH) command line: Use sudo. Example: sudo fdisk -lu To open a [i]graphical[/i] application (a text editor, a file manager), use either kdesudo or kdesu (see above). = = = = = = = = = = = = = = = = = = = = [b]Permissions: read, write, execute; change the execute bit[/b] See Part 2 of Commands at Konsole: Beginners: 3 parts http://kubuntuforums.net/forums/index.php?topic=3091607.0 Ownership and Permissions Use ls -l to see them; chown & chmod to change them. See tuxfiles http://www.tuxfiles.org/linuxhelp/filepermissions.html (symbolic mode) Here's a brief reminder sheet for those who know this stuff: [u]Setting ownership and permissions in GUI[/u] Open Konqueror or Dolphin as root (kdesudo konqueror), navigate to the file or directory, right-click, Properties, Permission, make changes, OK. In Konqueror/Dolphin, click the Advanced Permissions button to see all choices: owner, group, others and read, write, execute. [u]CLI[/u] owner--group--others For each class: read, write, execute ls -l: list files, use a long listing format => shows ownership and permissions Permissions – numerical mode There are 8 possibilities (2*2*2) for read (on or off) - write (on or off) - execute (on or off) permissions on a file or directory (2*2*2 = 8 ). The octal equivalents for these binary numbers are: 0: ---; 1: --x; 2: -w-; 3: -wx; 4: r--; 5: r-x; 6: rw-: 7: rwx 744: Owner can do anything, Group can only read, Others can only read Permissions – symbolic mode Suppose the file xyzfile is owned by root. [u]To make it executable[/u] for ALL users sudo chmod +x xyzfile [u]To remove the execute permission[/u] from all users sudo chmod -x xyzfile --> See Tuxfiles = = = = = = = = = = = = = = = = = = = = [b]Chroot -- how to[/b] From, Part 3 of Commands at Konsole: Beginners: 3 parts http://kubuntuforums.net/forums/index.php?topic=3091607.0 To “chroot into a partition” is to enter the partition with root privileges (“as root”). (The root directory is set equal to the partition.) Here's how: Let's say Kubuntu is in partition sda2, something is broken there, and you need to use your Kubuntu Live CD to chroot into sda2 and fix the problem. From the Live Kubuntu CD at Konsole: sudo mkdir /media/fixthings sudo mount /dev/sda2 /media/fixthings sudo chroot /media/fixthings => Now you are “in” sda2 “as root” and can work from there as if you were actually booted into it. The command prompt is a root prompt “... :/#” You can enter the commands you will use to fix the problem in sda2. When done, type exit to leave the root prompt: exit Now the prompt is a regular, non-root prompt “... :~$” To be safe, unmount the partition: sudo umount /dev/sda2 /media/fixthings => CAUTION Do not use chroot unless you know what you are doing; you can damage your Kubuntu filesystem if you make a mistake while using chroot. = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = = [b]References[/b] Grub 2 Basics, by drs305 http://ubuntuforums.org/showthread.php?t=1195275 Absolutely excellent treatment of editing the boot menu and some basic key concepts of Grub 2. Grub 2 Manual http://grub.enbug.org/Manual We hope this will be all you need, along with the man pages. GRUB 2: Live CD Install Guide http://grub.enbug.org/Grub2LiveCdInstallGuide Looks like this is the original and definitive treatment as of 9-9-2009. GNU GRUB 1.96/2 http://members.iinet.net/%7Eherman546/p20.html Looks like an encyclopedic, comprehensive coverage. GRUB 2 now default for new installations https://lists.ubuntu.com/archives/ubuntu-devel-announce/2009-June/000573.html Grub 2 now default for Ubuntu 9.10 http://www.ubuntugeek.com/grub-2-now-default-for-ubuntu-910-karmic-koala.html GRUB 2 -- Ubuntu Wiki -- FrontPage http://grub.enbug.org/ GRUB 2 -- Ubuntu Wiki https://wiki.ubuntu.com/Grub2 [b]FranklinPiat, Wiki -- good stuff![/b] Grub v2 manual, Manpages http://grub.enbug.org/FranklinPiat/GrubManual GRUB 2, official site http://www.gnu.org/software/grub/grub-2.en.html GNU GRUB, main site, Legacy GRUB http://www.gnu.org/software/grub/ GRUB Wiki: grub.cfg http://grub.enbug.org/grub.cfg GRUB 2 Commands, GRUB Wiki http://grub.enbug.org/CommandList Compares GRUB Legacy to GRUB 2 commands. StartUp-Manager https://help.ubuntu.com/community/StartUpManager GRUB & GRUB 2 Boot Process http://www.pixelbeat.org/docs/disk/ Bootloader http://en.wikipedia.org/wiki/Boot_loader GNU GRUB http://en.wikipedia.org/wiki/GRUB Boot Options https://help.ubuntu.com/community/BootOptions Kernel Parameters http://www.kernel.org/doc/Documentation/kernel-parameters.txt Grub Legacy -- How To GRUB Methods - Toolkit http://kubuntuforums.net/forums/index.php?topic=3081671.0 GParted Live CD http://gparted.sourceforge.net/livecd.php For partitioning, formatting your hard drive. Super Grub Disk http://www.supergrubdisk.org/ Will boot you into your OS when you can't do it alone. Arch Linux, ArchWiki GRUB 2 http://wiki.archlinux.org/index.php/GRUB2 Experiences in the Community, Jaunty and GRUB2 http://flossexperiences.wordpress.com/2008/11/19/jaunty-and-grub2/ GRUB 2 installation http://www.techenclave.com/guides-and-tutorials/grub-2-installation-92883.html GRUB2 Theming http://ubuntuforums.org/showthread.php?t=1182436 KernelTeam/Grub2Testing https://wiki.ubuntu.com/KernelTeam/Grub2Testing Using UUID https://help.ubuntu.com/community/UsingUUID BIOS Boot Partition, and what does GRUB use it for? http://grub.enbug.org/BIOS_Boot_Partition GUID Partition Table http://en.wikipedia.org/wiki/GUID_Partition_Table Technical Note TN2166, Secrets of the GPT http://developer.apple.com/mac/library/technotes/tn2006/tn2166.html Boot an iso via Grub 2 http://michael-prokop.at/blog/2009/05/25/boot-an-iso-via-grub2/ MultiBoot USB with Grub2 (boot directly from iso files) http://www.panticz.de/MultiBootUSB GRUB Graphical Menu Development Journal http://grub.gibibit.com/Journal Debian Wiki, GRUB, grub.cfg http://wiki.debian.org/Grub/grub.cfg.manpage As of 9-9-09, it doesn't exist. Tweaking GRUB 2 http://www.drlock.com/blog/2008/07/11/tweaking-grub-2/ GRUB 2 configuration, shirish http://www.techenclave.com/guides-and-tutorials/grub-2-configuration-93512.html How To Install GRUB 2 On Ubuntu 9.04 http://www.linuxtoday.com/news_story.php3?ltsn=2009-09-02-005-35-OS-HL-SM Making a Dedicated Grub Partition http://www.troubleshooters.com/linux/grub/grubpartition.htm Konsole, command line: Commands at Konsole: Beginners: 3 parts http://kubuntuforums.net/forums/index.php?topic=3091607.0 and tuxfiles http://www.tuxfiles.org/linuxhelp/dirs.html Permissions, filesystems, using the command line.

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