GRUB Commands

Garv58160228

New Member
GRUB has a powerful command line option. All you have to do to start the command line is to use the command grub.



You can see a list of the possible commands by using the help.

PHP Code:
grub> help
blocklist FILE boot
cat FILE chainloader [--force] FILE
clear color NORMAL [HIGHLIGHT]
configfile FILE device DRIVE DEVICE
displayapm displaymem
find FILENAME geometry DRIVE [CYLINDER HEAD SECTOR [
halt [--no-apm] help [--all] [PATTERN ...]
hide PARTITION initrd FILE [ARG ...]
kernel [--no-mem-option] [--type=TYPE] makeactive
map TO_DRIVE FROM_DRIVE md5crypt
module FILE [ARG ...] modulenounzip FILE [ARG ...]
pager [FLAG] partnew PART TYPE START LEN
parttype PART TYPE quit
reboot root [DEVICE [HDBIAS]]
rootnoverify [DEVICE [HDBIAS]] serial [--unit=UNIT] [--port=PORT] [--
setkey [TO_KEY FROM_KEY] setup [--prefix=DIR] [--stage2=STAGE2_
terminal [--dumb] [--no-echo] [--no-ed terminfo [--name=NAME --cursor-address
testvbe MODE unhide PARTITION
uppermem KBYTES vbeprobe [MODE]



The displaymem command will show you what GRUB thinks is the system address space map of the machine. The lower memory is the address space in the first megabyte of memory.

PHP Code:
grub> displaymem
EISA Memory BIOS Interface is present
Address Map BIOS Interface is present
Lower memory: 640K, Upper memory (to first chipset hole): 3072K
[Address Range Descriptor entries immediately follow (values are 64-bit)]
Usable RAM: Base Address: 0x0 X 4GB + 0x0,
Length: 0x0 X 4GB + 0xa0000 bytes
Reserved: Base Address: 0x0 X 4GB + 0xa0000,
Length: 0x0 X 4GB + 0x60000 bytes
Usable RAM: Base Address: 0x0 X 4GB + 0x100000,
Length: 0x0 X 4GB + 0x300000 bytes




PHP Code:
grub> find /sbin/init
(hd0,1)


enter find ( and then tab

PHP Code:
grub> find (hd0,


Use the tab
PHP Code:
grub> find (hd0,
Possible partitions are:
Partition num: 0, Filesystem type is ext2fs, partition type 0x83
Partition num: 1, Filesystem type is ext2fs, partition type 0x83
Partition num: 2, Filesystem type is ext2fs, partition type 0x83
Partition num: 4, Filesystem type unknown, partition type 0x8e
Partition num: 5, Filesystem type unknown, partition type 0x8e

Disk /dev/hda: 8589 MB, 8589934592 bytes
255 heads, 63 sectors/track, 1044 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 13 104391 83 Linux
/dev/hda2 14 523 4096575 83 Linux
/dev/hda3 524 650 1020127+ 83 Linux
/dev/hda4 651 1044 3164805 5 Extended
/dev/hda5 651 663 104391 8e Linux LVM
/dev/hda6 664 676 104391 8e Linux LVM

grub> find /grub/menu.lst
(hd0,0)



PHP Code:
grub> find /sbin/init
(hd0,1)
 
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