Howto: Verify Downloaded Linux / BSD DVD or CD ISO images for integrity

Posted on in Categories CentOS, Debian Linux, Howto, Linux, Linux distribution, RedHat/Fedora Linux, Security, Sys admin, Tip of the day, Ubuntu Linux, UNIX last updated July 26, 2007

You need to verify that that downloaded Linux DVD or ISO images are intact before you burn and use them. This is security feature. But how do you verify ISO images?

Answer is quite simple use md5sum command to compute and check MD5 message digest.

Why verify ISO images?

a) To protect yourself
b) Verify that a file has not changed as a result of file transfer, disk error, cracker attacks, etc.

How does it work?

When you run md5sum command on ISO file, you get checksum (or hash) on screen. You need to compare this checksum with original. It works as a compact digital fingerprint of a file. You can then compare the MD5 hash of your download ISO file, to the known good hash of the file you are checking. If the two values match, you are safe and use the ISO image.

Example

Let us download FreeBSD ISO image:
$ cd /tmp
$ wget ftp://ftp.freebsd.org/pub/FreeBSD/releases/i386/ISO-IMAGES/6.2/6.2-RELEASE-i386-bootonly.iso

Next download MD5 checksum:
$ wget ftp://ftp.freebsd.org/pub/FreeBSD/releases/i386/ISO-IMAGES/6.2/CHECKSUM.MD5

Generate MD5 hash for ISO image

$ md5sum 6.2-RELEASE-i386-bootonly.iso
Output:

4e8701ac951bc4537f8420fdac7efbb5  6.2-RELEASE-i386-bootonly.iso

Verify ISO image

See the known good hash of the file (6.2-RELEASE-i386-bootonly.iso):
$ md5sum -c CHECKSUM.MD5
Output:

6.2-RELEASE-i386-bootonly.iso: OK

You can also use following command for the same purpose:

A note for Windows XP / Vista users

Download of the day: e tool to extract rpm, rar, zip and other formats under Linux

Posted on in Categories Download of the day, Linux last updated July 10, 2007

Sure you can use unzip, unrar, and other tools to extract files under Linux. e is little tool that can extract almost any archive in Linux so you do not need to remember which tool and what command lines are necessary.

You need ruby lanaguage installed on your computer to use this tiny tool. Apart from Ruby, e uses the linux tool file to determine what kind of archive it is dealing with. This tool should be available on any proper Linux installation. Once e knows the archive type, the appropriate extraction tool is executed.

You can read more about this tool, installation and other notes at Martin Ankerl blog.

See also

Download of the day: Fedora 7 CD / DVD ISO

Posted on in Categories Download of the day, Linux, Linux desktop, Linux Embedded devices, RedHat/Fedora Linux last updated June 1, 2007

Update: Nov-25,2008: Fedora Linux 10 has been related and available for download.

Update: Nov-7,2007: Fedora Linux 8 has been related and available for download here.

Fedora 7 has been released. The Fedora Project is a Red Hat sponsored and community supported open source project. Its goal is the rapid progress of free and open source software and content. It offers cutting edge softwares for desktop usage. The latest version of the popular Linux distribution has a lot to offer users and developers.

New in Fedora 7

=> This release features GNOME 2.18 and KDE 3.5.6.

=> This release integrates Kernel-based Virtual Machine (KVM) technology with Fedora’s graphical virt-manager and command-line virsh tools. KVM provides a hardware accelerated virtualization solution, and users have a choice between KVM and Xen, along with Qemu, in this release.

=> In this release, the performance of yum, Pirut, and Pup have been significantly improved.

=> This release features integration of a new FireWire stack in the kernel for more robust device handling.

=> Fedora now includes improved power management through implementation of dynamic ticks in the kernel.

Fedora
(click to enlarge, more screenshots @ Fedora Website)

=> I can now install Fedora on my Sony VAIO Notebooks

=> See Fedora 7 release notes.

Download link – ( Download Fedora )

Download of the day: Fedora Core 7 CD / DVD ISO
You can download Fedora via the web/ftp server or via BitTorrent (recommended).

Fedora 7 DVD ISO download

= > Visit mirror to download Fedora ISO images (2.7 GB)

Fedora 7 Live CD ISO download

=> Use Live CD (700M) if internet connection is slow or you just want to see how Fedora works. You can install fedora from Live cd.

Fedora 7 DVD ISO BitTorrent download

=> Download from BitTorrent (requires a BitTorrent client)

How to: Extract files from ISO CD images in Linux

Posted on in Categories Debian Linux, File system, Gentoo Linux, Howto, Linux, RedHat/Fedora Linux, Suse Linux, Sys admin, Tips, Ubuntu Linux last updated April 27, 2004

Under many situations you may need to get a single file/many files from Linux ISO image.

You can mount ISO images via the loop device. You need to use mount command. First login as a root user:

Extract File(s) Under Linux OS

Let us assume that your ISO image name is disk1.iso.

Step # 1: First you need to create a directory /mnt/iso

# mkdir /mnt/iso
# mount -o loop disk1.iso /mnt/iso

Step # 3: Extract file

Now you can easily copy file called file.txt from iso disk image to /tmp directory :

# cd /mnt/iso
# cp file.txt /tmp

Step # 4: Copy foo.rpm from ISO disk image:

# cd /mnt/iso/RedHat/RPMS
# cp foo.rpm /tmp 

Extract File(s) Under Windows XP or Vista Os

Windows do not have in built capability as provided by Linux to extract file. Luckly many third party software exist my favorite is Winimage http://www.winimage.com/. Download trial version (I’m sure you will love to registered this tiny utility later):

1) Install Winimage software

2) Just double click on Linux ISO file

3) Select the desired file and hit CTRL + X (or from Image menu select extract)

For more information read man pages:

man cp
man mv
man rpm
man mount
man mkdir

How to: Mount an ISO image under Linux

Posted on in Categories Debian Linux, File system, Howto, Linux, RedHat/Fedora Linux, Suse Linux, Sys admin, Tips, Ubuntu Linux last updated March 29, 2004

An ISO image is an archive file (disk image) of an optical disc using a conventional ISO (International Organization for Standardization) format. ISO image files typically have a file extension of .ISO. The name “ISO” is taken from the ISO 9660 file system used with CD-ROM media, but an ISO image can also contain UDF file system because UDF is backward-compatible to ISO 9660.

You can mount an ISO images via the loop device under Linux. It is possible to specify transfer functions (for encryption/decryption or other purposes) using loop device.

But, how do you mount an ISO image under Linux? You need to use mount command as follows: