Grub command to boot Linux

Because of the curiosity about Linux system, want to press to play on the machine. After a busy night yesterday, Linux was finally installed. But a little too early to be happy, I thought into the Linux is like into Windows so simple, did not think but jumped out a boot command (grub), let me guide, I look numb. It's not a bit. There is no way I can not endure, I shut down the computer to sleep. Today at noon, online search information. To acquaint the command with the other side. But it was a tough look. Tried a few times or not. I didn't get it. Ben was going to give up. I didn't expect to be inspired in the afternoon. Knock on a few commands and go in.

This installation has made me learn a lot. Here is the main talk in grub down to boot Linux;

The steps are as follows;

A enter the Grub command mode.

b Familiarize yourself with some of the grub commands first Grub>help

C Familiar with cat commands

d root command to specify the partition where/boot is located

e kernel instructions to specify the Linux kernel, and the partition in which it resides

F Use the INITRD command to specify the INITRD file

G Boot Boot System

Use of the Cat command

The cat instruction is used to view the contents of the file, sometimes we do not know the Linux/boot partition, and/or the location of the root partition, to see/etc/fstab content to know, at this time, we need to use the cat (Hd[0-n],y)/etc/fstab to obtain these content Note to learn to use the TAB key command to complement the function;

Grub> Cat (Press the TAB key to come out hd0 or HD1, etc.;
Grub> Cat (hd0, note: Enter the hd0, and then press the TAB key;
Grub> Cat (hd0,6)
Possible partitions is:
Partition num:0, Filesystem type unknown, Partition type 0x7
Partition num:4, Filesystem type is fat, Partition type 0xb
Partition num:5, Filesystem type is ReiserFS, Partition type 0x83
Partition num:6, Filesystem type is EXT2FS, Partition type 0x83
Partition num:7, Filesystem type unknown, Partition type 0x83
Partition Num:8, Filesystem type is ReiserFS, Partition type 0x83
Partition num:9, Filesystem type unknown, Partition type 0x82

Grub> Cat (hd0,6)/etc/fstab Note: For example I would like to check (hd0,6)/etc/fstab The contents of this input;

label=//ext3 Defaults 1 1
/dev/devpts/dev/pts devpts gid=5,mode=620 0 0
/DEV/SHM/DEV/SHM TMPFS Defaults 0 0
/DEV/PROC/PROC proc Defaults 0 0
/dev/sys/sys Sysfs Defaults 0 0
LABEL=SWAP-HDA1 swap swap defaults 0 0
/dev/hdc/media/cdrecorder Auto Pamconsole,exec,noauto,
Managed 0 0

Main view of the content in the/etc/fstab, mainly Linux/partition and/boot is a separate partition, if there is no/boot similar line, proof/boot and Linux/on the same hard disk partition, such as the above example label=/this line is extremely important ; The Linux system is in a partition labeled label=/;

If your Linux system/boot and/are not on the same partition, Cat (hd[a-n],y) may have found something similar to the following;

LABEL=/                 /                       ext3    defaults        1 1
LABEL=/boot             /boot                   ext3    defaults        1 2

root (hd[0-n,y) 指令来指定/boot所在的分区；


In fact, this root (hd[0,n],y) can be omitted, if omitted, we have to specify in the KERENL command, we have already said (Hd[0-n],y) The use of the hard disk partition representation, mainly used to specify the partition of/boot;

eg

grub> root (hd0,0)

kernel 指令，用来指定Linux的内核，及/所在的分区；


Kernel This instruction may be a beginner a little afraid, do not know which partition the kernel, and the full name of the kernel file name. Do not forget the TAB key command to complement the application;

If we have specified the/boot partition by root (hd[0-n],y), there are two syntax:

If/boot and Linux are in the same partition, it should be in one of the following formats;

Kernel/boot/vmlinuz Here Press the TAB key to make up, see the kernel full name of the RO root=/dev/hd[a-z]x

If/boot has its own separate partition, it should be;

Kernel/vmlinuz Here Press the TAB key to make up, see the kernel full name of the RO root=/dev/hd[a-z]x

Here root=/dev/hd[a-z]x is the partition where the Linux/root is located, if you do not know which partition it is, use tab-out to calculate, one by one, or use Cat (hd[0-n],y)/etc/fstab to get Linux/ The label of the partition or partition in which it resides;

grub> kernel /boot/在这里按tab键；这样就列出/boot中的文件了； 
Possible files are: grub initrd-2.6.11-1.1369_FC4.img System.map-2.6.11-1.1369
_FC4 config-2.6.11-1.1369_FC4 vmlinuz-2.6.11-1.1369_FC4 grubBAK memtest86+-1.55
.1 xen-syms xen.gz

grub> kernel /boot/vmlinuz-2.6.11-1.1369_FC4 ro root=LABEL=/  
   [Linux-bzImage, setup=0x1e00, size=0x18e473]


Note: root=label=/is the label of the file system of the Linux/partition, and if you know the specific partition of Linux/in which it is located, use Root=/dev/hd[a-z]x to specify the line. For example, the following line is also possible;

grub> kernel /boot/vmlinuz-2.6.11-1.1369_FC4 ro root=/dev/hda7

You can also omit the specified root (hd[0-n],y) of the partition in which the/boot is located, and specify the partition of/boot in the kernel directly, so it is in the following syntax;

If this is the same partition AS/boot and Linux root;

kernel (hd[0-n],y)/boot/vmlinuz ro root=/dev/hd[a-z]X

Like what:

grub>kernel

If the root of/boot and Linux is not in a partition;

kernel (hd[0-n],y)/vmlinuz  ro root=/dev/hd[a-z]X grub> kernel (hd0,0)/boot/vmlinuz-2.6.11-1.1369_FC4 ro root=/dev/hda7 
   [Linux-bzImage, setup=0x1e00, size=0x18e473]

or the following input, the cat out of the/etc/fstab content prevail;

grub> kernel (hd0,0)/boot/vmlinuz-2.6.11-1.1369_FC4 ro root=LABEL=/
   [Linux-bzImage, setup=0x1e00, size=0x18e473]

INITRD the command line to specify the INITRD file;

grub> initrd /boot/initrd在这里tab 来补齐；
grub> initrd /boot/initrd-2.6.11-1.1369_FC4.img
   [Linux-initrd @ 0x2e1000, 0x10e685 bytes]

If/boot is a separate partition, the syntax should look like this;

grub> initrd /initrd在这里tab 来补齐；
grub> initrd /initrd-2.6.11-1.1369_FC4.img
   [Linux-initrd @ 0x2e1000, 0x10e685 bytes]

Boot boot system;

grub>boot 下面是在我机器上的命令： grub> Cat (hd0,0)/etc/fstab
# This file was edited by Fstab-sync-see ' Man Fstab-sync ' for details
label=//ext3 Defaults 1 1
/dev/devpts/dev/pts devpts gid=5,mode=620 0 0
/DEV/SHM/DEV/SHM TMPFS Defaults 0 0
/DEV/PROC/PROC proc Defaults 0 0
/dev/sys/sys Sysfs Defaults 0 0
LABEL=SWAP-HDA1 swap swap defaults 0 0

/dev/hdc/media/cdrecorder Auto pamconsole,exec,noauto,managed 0 0

grub> Root (hd0,0)
Filesystem type is EXT2FS, partition type 0x83

grub> kernel/boot/Press TAB here to complete the full list of/boot files;
Possible files Are:grub initrd-2.6.11-1.1369_fc4.img system.map-2.6.11-1.1369_fc4 config-2.6.11-1.1369_fc4 Vmlinuz-2.6.11-1.1369_fc4
memtest86+-1.55.1 xen-syms xen.gz

grub> kernel/boot/vmlinuz-2.6.11-1.1369_fc4 ro root=label=/
[Linux-bzimage, setup=0x1e00, size=0x18e473]

grub> initrd/boot/Press TAB here to complement
Possible files Are:grub initrd-2.6.11-1.1369_fc4.img system.map-2.6.11-1.1369_fc4 config-2.6.11-1.1369_fc4 VMLINUZ-2.6.11-1.1369_FC4 Grubbak
memtest86+-1.55.1 xen-syms xen.gz

grub> initrd/boot/initrd-2.6.11-1.1369_fc4.imgNote: Enter the full name of the INTRD file name;
[Linux-initrd @ 0x2e1000, 0x10e685 bytes]

grub> Boot 以上也就这么多，还须自己多揣摩

Grub command to boot Linux