Grub command to guide Linux

I'm curious about the Linux system and want to play on the machine. I spent one night busy yesterday and finally installed Linux. But it was a little too early. I thought it was as simple as entering Linux. I didn't think it was as easy as popping up a pilot command (grub) To Let me guide, I saw it numb. Not at all. There is no way I can't help it. I just shut down and went to bed. At noon today, I went online to check information. Familiarize yourself with the relevant commands. However, it is quite difficult. I tried it several times but it still didn't work. I did not get it. I was about to give up. I didn't think of inspiration in the afternoon. Just press a few commands.

This installation has taught me a lot. The following describes how to guide Linux under grub;

The procedure is as follows;

A enters the grub command mode.

B. Get familiar with some grub commands.

C. Get familiar with Cat commands.

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

E kernel command to specify the Linux kernel and partition

F use the initrd command to specify the initrd File

G boot System

Cat command usage

The cat command is used to view the file content. Sometimes we do not know the Linux/boot partition and the location of the/root partition. We need to check the/etc/fstab content to find out, we need to use CAT (HD [0-n], Y)/etc/fstab to obtain the content. Be sure to use the tab command to complete the function;

grub> CAT (hd0 or hd1 is displayed by pressing the tab key;
grub> CAT (hd0, note: Enter hd0, and then press the tab key;
grub> CAT (hd0, 6)
Possible partitions are:
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 want to check (hd0, 6) enter the/etc/fstab content in this way.

Label = // ext3 defaults 1 1
/Dev/devpts/dev/PTS devpts gid = 5, mode = 620 0 0
/Dev/SHM tmpfs defaults 0 0
/Dev/proc defaults 0 0
/Dev/sys sysfs defaults 0 0
Label = SWAP-hda1 swap defaults 0 0
/Dev/HDC/Media/cdrecorder auto pamconsole, exec, noauto,
Managed 0 0

Check the content in/etc/fstab, mainly including Linux/partition and whether/boot is an independent partition. If there is no line similar to/boot, verify that/boot and Linux/are in the same hard disk partition. For example, label =/is very important in the above example. It indicates that the Linux system is in the partition labeled label =;

If your Linux system/boot and/are not in the same partition, CAT (HD [A-N], Y) may find something similar to the following;

Label = // ext3 defaults 1 1
Label =/boot ext3 defaults 1 2

Root (HD [0-n, Y) command to specify the partition where/boot is located;


In fact, this root (HD [0, N], Y) can be omitted. If it is omitted, We need to specify it in the kerenl command. We have already said (HD [0-n], y) usage of the hard disk partition representation method; it is mainly used to specify the partition where/boot is located;

Eg:

Grub> root (hd0, 0)

The kernel command is used to specify the Linux kernel and the partition where/is located;


The kernel command may be a bit scary for beginners. I don't know which partition the kernel is in and what is the full name of the kernel file name. Do not forget the tab key command completion application;

If the/boot partition is specified through root (HD [0-n], Y), The syntax is as follows:

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

Kernel/boot/vmlinuz press the tab key here to complete the kernel, and you will see the full kernel name Ro root =/dev/HD [A-Z] x

If/boot has its own independent partitions, it should be;

Kernel/vmlinuz press the tab key here to complete the kernel, and you will see the full name of the kernel 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 is located, use a tab to calculate it, try one by one; or use CAT (HD [0-n], Y)/etc/fstab to obtain the partition or partition label of Linux;

Grub> kernel/boot/press the tab key here to list the files in/boot;
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 & gt; 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. If you know the specific partition of Linux, use root =/dev/HD [A-Z] X to specify the operation. For example, the following row is acceptable;

Grub> kernel/boot/vmlinuz-2.6.11-1.1369_FC4 Ro root =/dev/hda7

You can also delete the specified root (HD [0-n], Y) of the partition where/boot is located, and directly specify the partition where/boot is located in the kernel; so it is in the following syntax;

If it is a partition at the same root of/boot and Linux;

Kernel (HD [0-n], Y)/boot/vmlinuz Ro root =/dev/HD [A-Z] x

For example:

Grub> kernel

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

Kernel (HD [0-n], Y)/vmlinuz Ro root =/dev/HD [A-Z] x Grub & gt; 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 is based on the content of CAT/etc/fstab;

Grub> kernel (hd0, 0)/boot/vmlinuz-2.6.11-1.1369_FC4 Ro root = label =/
[Linux-bzimage, setup = 0x1e00, size = 0x18e473]

The initrd command line is used to specify the initrd file;

Grub> initrd/boot/initrd tab here to complete;
Grub> initrd/boot/initrd-2.6.11-1.1369_FC4.img
[Linux-initrd @ 0x2e1000, 0x10e685 bytes]

If/boot is an independent partition, it should look like the following syntax; for example, the following;

Grub> initrd/initrd tab here to complete;
Grub> initrd/initrd-2.6.11-1.1369_FC4.img
[Linux-initrd @ 0x2e1000, 0x10e685 bytes]

Boot System;

Grub> boot The following is a command on my machine:

Grub> CAT (hd0, 0)/etc/fstab
# This file is 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 tmpfs defaults 0 0
/Dev/proc defaults 0 0
/Dev/sys sysfs defaults 0 0
Label = SWAP-hda1 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/Click tab to complete the list of all/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 & gt; kernel/boot/vmlinuz-2.6.11-1.1369_FC4 Ro root = label =/
[Linux-bzimage, setup = 0x1e00, size = 0x18e473]

Grub> initrd/boot/Click tab here to complete
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> bootThere are so many of the above, you have to learn more