Enhanced partition copy script (new & improved!) Post: 302448738

Sponsored Content

Top Forums Shell Programming and Scripting Enhanced partition copy script (new & improved!) Post 302448738 by jwzumwalt on Friday 27th of August 2010 12:00:50 AM

08-27-2010

Registered User

I'm not sure I understand what you are asking but here is a bit of additional information that may or may not answer your question.

The partition information for an entire drive is kept in the MBR (master boot record). There is no separate or individual information block available. Therefore my program (and any other) that attempts to save the first 512 bytes of a partition (which is the mbr) for any partition other than the first will receive an error.

My program does not attempt to stop someone from saving an invalid MBR block on other partitions. dd is smart enough to notice that an attempt is being made to save the MBR of an invalid partition and will shoot out an error message, but it still saves the invalid 512 byte block.

This first example will work because the mbr is actualy at the start of partition 1

Code:

dd if=hda1 of=partition.mbr.img count=1 bs=512

This example will cause an error message because the 2nd partition does not have an mbr!

Code:

dd if=hda2 of=partition.mbr.img count=1 bs=512

My thinking is that there may be some special case that I am not aware of that a user may need that 512 byte block. So, I trust the users judgment.

In the future, I will place some type of error trap and give sa message to the user that explains what is going on.

I hope this information helps.

Jan Zumwalt

jwzumwalt

View Public Profile for jwzumwalt

Find all posts by jwzumwalt

9 More Discussions You Might Find Interesting

1. Gentoo

How to copy single partition?

I presently backup my multi-OS multi-paritition boot drive (fedora core 4/ext3, WinXPServer/NTFS, WinXPHome/FAT32) with the command: telinit 1; cp /dev/sda /dev/sdb And this works. Is there a command to only copy a single partition instead of an entire device? And what about the grub...

2. UNIX for Dummies Questions & Answers

slice & partition???

:confused: Hello, What is the difference between slice and partition on Solaris world? Regards

3. Shell Programming and Scripting

How do I search first&second string & copy all content between them to other file?

Hi All, How do I search first string & second string and copy all content between them from one file to another file? Please help me.. Thanks In Advance. Regards, Pankaj

4. UNIX for Advanced & Expert Users

copy a whole partition excluding specified.

Scenario: I would want to copy my / to /mnt, and to avoid recursion exclude /mnt. cp -avx / /mnt If i use the above i believe it would run recursively, and end up in mess. So how to do it ?! Basically this / is sda1, and /mnt is sda2 and sda1 is where only OS is available & currently...

5. Shell Programming and Scripting

Perl Script to find & copy words from Web.

I need to write a perl script to search for a specific set of numbers that occur after a series of words but before another. Specifically, I need to locate the phrase today at the summit, then immediately prior to the words tonnes/day copy the number that will be between 100 and 9,999, for example,...

6. Filesystems, Disks and Memory

Using dd to copy a partition.

Here's a conundrum. I use a ThinkPad (T30) which has a slot on the side for the hard drive. It is very easy to swap this with another hard drive which I keep as a backup. Now when I copy the Linux partition from my (in use) hard drive to the backup one (in my UltraBay slot) it takes only 30...

7. Shell Programming and Scripting

Compare & Copy Directories : Bash Script Help

Beginner/Intermediate shell; comfortable in the command line. I have been looking for a solution to a backup problem. I need to compare Directory 1 to Directory 2 and copy all modified or new files/directories from Directory 1 to Directory 3. I need the directory and file structure to be...

8. Shell Programming and Scripting

Script to overwrite & before that keep copy a file on many servers

I have ssh password less auth enable & script does the job well as well #/bin/bash for i in `cat ip` do scp /etc/resolv.conf root@$ip done But I need to take backup of the file i will overwrite .. is there any simple way ? Kindly respond

9. Red Hat

Shrink LVM partition & create new Linux Primary partition

Hello All, I have a Red Hat Linux 5.9 Server installed with one hard disk & 2 Partitions created on it as follows, /boot - Linux Partition & another is LVM - One VG & under that 5-6 Logical volumes(var,opt,home etc). Here my requirement is to take out 1GB of space from LVM ( Any logical...

LEARN ABOUT BSD

disktab

DISKTAB(5)							File Formats Manual							DISKTAB(5)

NAME

       disktab - disk description file

SYNOPSIS

       #include <disktab.h>

DESCRIPTION

       Disktab	is a simple date base which describes disk geometries and disk partition characteristics.  The format is patterned after the term-
       cap(5) terminal data base.  Entries in disktab consist of a number of `:' separated fields.  The first entry for each disk gives the  names
       which are known for the disk, separated by `|' characters.  The last name given should be a long name fully identifying the disk.

       The following list indicates the normal values stored for each disk entry.

       Name  Type  Description
       ns    num   Number of sectors per track
       nt    num   Number of tracks per cylinder
       nc    num   Total number of cylinders on the disk
       b0    str   Filename of block zero primary bootstrap for device
       ba    num   Block size for partition `a' (bytes)
       bd    num   Block size for partition `d' (bytes)
       be    num   Block size for partition `e' (bytes)
       bf    num   Block size for partition `f' (bytes)
       bg    num   Block size for partition `g' (bytes)
       bh    num   Block size for partition `h' (bytes)
       fa    num   Fragment size for partition `a' (bytes)
       fd    num   Fragment size for partition `d' (bytes)
       fe    num   Fragment size for partition `e' (bytes)
       ff    num   Fragment size for partition `f' (bytes)
       fg    num   Fragment size for partition `g' (bytes)
       fh    num   Fragment size for partition `h' (bytes)
       pa    num   Size of partition `a' in sectors
       pb    num   Size of partition `b' in sectors
       pc    num   Size of partition `c' in sectors
       pd    num   Size of partition `d' in sectors
       pe    num   Size of partition `e' in sectors
       pf    num   Size of partition `f' in sectors
       pg    num   Size of partition `g' in sectors
       ph    num   Size of partition `h' in sectors
       se    num   Sector size in bytes (default 512)
       sf    bool  supports bad144-style bad sector forwarding
       so    bool  partition offsets in sectors
       ty    str   Type of disk (e.g. removable, winchester)

       Disktab entries may be automatically generated with the diskpart program.

FILES

       /etc/disktab

SEE ALSO

       newfs(8), diskpart(8), getdiskbyname(3)

BUGS

       This file shouldn't exist, the information should be stored on each disk pack.

4.2 Berkeley Distribution					   May 17, 1986 							DISKTAB(5)