Installing Ubuntu from a Unix/Linux System

This section explains how to install Ubuntu from an existing Unix or Linux system, without using the menu-driven installer as explained in the rest of the manual. This cross-install HOWTO has been requested by users switching to Ubuntu from Debian GNU/Linux, Red Hat, Mandrake, and SUSE. In this section some familiarity with entering *nix commands and navigating the file system is assumed. In this section, $ symbolizes a command to be entered in the user's current system, while # refers to a command entered in the Ubuntu chroot.

Once you've got the new Ubuntu system configured to your preference, you can migrate your existing user data (if any) to it, and keep on rolling. This is therefore a zero downtime Ubuntu install. It's also a clever way for dealing with hardware that otherwise doesn't play friendly with various boot or installation media.


As this is a mostly manual procedure, you should bear in mind that you will need to do a lot of basic configuration of the system yourself, which will also require more knowledge of Ubuntu and of Linux in general than performing a regular installation. You cannot expect this procedure to result in a system that is identical to a system from a regular installation. You should also keep in mind that this procedure only gives the basic steps to set up a system. Additional installation and/or configuration steps may be needed.

Getting Started

With your current *nix partitioning tools, repartition the hard drive as needed, creating at least one filesystem plus swap. You need around 350MB of space available for a console only install, or about 1GB if you plan to install X (more if you intend to install desktop environments like GNOME or KDE).

Next, create file systems on the partitions. For example, to create an ext3 file system on partition /dev/hda6 (that's our example root partition):

# mke2fs -j /dev/hda6

To create an ext2 file system instead, omit -j.

Initialize and activate swap (substitute the partition number for your intended Ubuntu swap partition):

# mkswap /dev/hda5
# sync; sync; sync
# swapon /dev/hda5

Mount one partition as /mnt/ubuntu (the installation point, to be the root (/) filesystem on your new system). The mount point name is strictly arbitrary, it is referenced later below.

# mkdir /mnt/ubuntu
# mount /dev/hda6 /mnt/ubuntu


If you want to have parts of the filesystem (e.g. /usr) mounted on separate partitions, you will need to create and mount these directories manually before proceding with the next stage.

Install debootstrap

The utility used by the Ubuntu installer, and recognized as the official way to install an Ubuntu base system, is debootstrap. It uses wget and ar, but otherwise depends only on /bin/sh and basic Unix/Linux tools[19]. Install wget and ar if they aren't already on your current system, then download and install debootstrap.

Or, you can use the following procedure to install it manually. Make a work folder for extracting the .deb into:

# mkdir work
# cd work

The debootstrap binary is located in the Ubuntu archive (be sure to select the proper file for your architecture). Download the debootstrap .deb from the pool, copy the package to the work folder, and extract the files from it. You will need to have root privileges to install the files.

# ar -x debootstrap_0.X.X_all.deb
# cd /
# zcat /full-path-to-work/work/data.tar.gz | tar xv

Run debootstrap

debootstrap can download the needed files directly from the archive when you run it. You can substitute any Ubuntu archive mirror for in the command example below, preferably a mirror close to you network-wise. Mirrors are listed at

If you have an Ubuntu intrepid CD mounted at /cdrom, you could substitute a file URL instead of the http URL: file:/cdrom/ubuntu/

Substitute one of the following for ARCH in the debootstrap command: amd64, hppa, i386, ia64, powerpc, or sparc.

# /usr/sbin/debootstrap --arch ARCH intrepid /mnt/ubuntu

Configure The Base System

Now you've got a real Ubuntu system, though rather lean, on disk. Chroot into it:

# LANG=C chroot /mnt/ubuntu /bin/bash

After chrooting you may need to set the terminal definition to be compatible with the Ubuntu base system, for example:

# export TERM=xterm-color

Create device files

At this point /dev/ only contains very basic device files. For the next steps of the installation additional device files may be needed. There are different ways to go about this and which method you should use depends on the host system you are using for the installation, on whether you intend to use a modular kernel or not, and on whether you intend to use dynamic (e.g. using udev) or static device files for the new system.

A few of the available options are:

  • create a default set of static device files using

    # cd /dev
    # MAKEDEV generic

  • manually create only specific device files using MAKEDEV

  • bind mount /dev from your host system on top of /dev in the target system; note that the postinst scripts of some packages may try to create device files, so this option should only be used with care

Mount Partitions

You need to create /etc/fstab.

# editor /etc/fstab

Here is a sample you can modify to suit:

# /etc/fstab: static file system information.
# file system    mount point   type    options                  dump pass
/dev/XXX         /             ext3    defaults                 0    1
/dev/XXX         /boot         ext3    ro,nosuid,nodev          0    2

/dev/XXX         none          swap    sw                       0    0
proc             /proc         proc    defaults                 0    0
sys              /sys          sysfs   defaults                 0    0

/dev/fd0         /media/floppy auto    noauto,rw,sync,user,exec 0    0
/dev/cdrom       /media/cdrom  iso9660 noauto,ro,user,exec      0    0

/dev/XXX         /tmp          ext3    rw,nosuid,nodev          0    2
/dev/XXX         /var          ext3    rw,nosuid,nodev          0    2
/dev/XXX         /usr          ext3    rw,nodev                 0    2
/dev/XXX         /home         ext3    rw,nosuid,nodev          0    2

Use mount -a to mount all the file systems you have specified in your /etc/fstab, or, to mount file systems individually, use:

# mount /path   # e.g.: mount /usr

Current Ubuntu systems have mountpoints for removable media under /media, but keep compatibility symlinks in /. Create these as as needed, for example:

# cd /media
# mkdir cdrom0
# ln -s cdrom0 cdrom
# cd /
# ln -s media/cdrom

You can mount the proc and sysfs file systems multiple times and to arbitrary locations, though /proc and /sys respectively are customary. If you didn't use mount -a, be sure to mount proc and sysfs before continuing:

# mount -t proc proc /proc
# mount -t sysfs sysfs /sys

The command ls /proc should now show a non-empty directory. Should this fail, you may be able to mount proc from outside the chroot:

# mount -t proc proc /mnt/ubuntu/proc

Setting Timezone

An option in the file /etc/default/rcS determines whether the system will interpret the hardware clock as being set to UTC or local time. The following command allow you to set that and choose your timezone.

# editor /etc/default/rcS
# tzconfig

Configure Networking

To configure networking, edit /etc/network/interfaces, /etc/resolv.conf, /etc/hostname and /etc/hosts.

# editor /etc/network/interfaces

Here are some simple examples from /usr/share/doc/ifupdown/examples:

# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
# See the interfaces(5) manpage for information on what options are
# available.

# We always want the loopback interface.
auto lo
iface lo inet loopback

# To use dhcp:
# auto eth0
# iface eth0 inet dhcp

# An example static IP setup: (broadcast and gateway are optional)
# auto eth0
# iface eth0 inet static
#     address
#     network
#     netmask
#     broadcast
#     gateway

Enter your nameserver(s) and search directives in /etc/resolv.conf:

# editor /etc/resolv.conf

A simple example /etc/resolv.conf:

search hqdom.local

Enter your system's host name (2 to 63 characters):

# echo UbuntuHostName > /etc/hostname

And a basic /etc/hosts with IPv6 support: localhost UbuntuHostName

# The following lines are desirable for IPv6 capable hosts
::1     ip6-localhost ip6-loopback
fe00::0 ip6-localnet
ff00::0 ip6-mcastprefix
ff02::1 ip6-allnodes
ff02::2 ip6-allrouters
ff02::3 ip6-allhosts

If you have multiple network cards, you should arrange the names of driver modules in the /etc/modules file into the desired order. Then during boot, each card will be associated with the interface name (eth0, eth1, etc.) that you expect.

Configure Apt

Debootstrap will have created a very basic /etc/apt/sources.list that will allow installing additional packages. However, you may want to add some additional sources, for example for source packages and security updates:

deb-src intrepid main

deb intrepid-security main
deb-src intrepid-security main

Make sure to run aptitude update after you have made changes to the sources list.

Configure Locales and Keyboard

To configure your locale settings to use a language other than English, install the appropriate language packs and configure them. Currently the use of UTF-8 locales is recommended.

# aptitude install language-pack-de language-pack-gnome-de

To configure your keyboard (if needed):

# aptitude install console-setup
# dpkg-reconfigure console-setup

Note that the keyboard cannot be set while in the chroot, but will be configured for the next reboot.

Install a Kernel

If you intend to boot this system, you probably want a Linux kernel and a boot loader. Identify available pre-packaged kernels with:

# apt-cache search linux-image

If you intend to use a pre-packaged kernel, you may want to create the configuration file /etc/kernel-img.conf before you do so. Here's an example file:

# Kernel image management overrides
# See kernel-img.conf(5) for details
do_symlinks = yes
relative_links = yes
do_bootloader = yes
do_bootfloppy = no
do_initrd = yes
link_in_boot = no

For detailed information about this file and the various options, consult its man page which will be available after installing the kernel-package package. We recommend that you check that the values are appropriate for your system.

Then install the kernel package of your choice using its package name.

# aptitude install linux-image-2.6.25-arch-etc

If you did not create a /etc/kernel-img.conf before installing a pre-packaged kernel, you may be asked some questions during its installation that refer to it.

Set up the Boot Loader

To make your Ubuntu system bootable, set up your boot loader to load the installed kernel with your new root partition. Note that debootstrap does not install a boot loader, though you can use aptitude inside your Ubuntu chroot to do so.

Note that this assumes that a /dev/hda device file has been created. There are alternative methods to install grub, but those are outside the scope of this appendix.

Check man yaboot.conf for instructions on setting up the bootloader. If you are keeping the system you used to install Ubuntu, just add an entry for the Ubuntu install to your existing yaboot.conf. You could also copy it to the new system and edit it there. After you are done editing, call ybin (remember it will use yaboot.conf relative to the system you call it from).

Here is a basic /etc/yaboot.conf as an example:


On some machines, you may need to use ide0: instead of hd:.

Finishing touches

As mentioned earlier, the installed system will be very basic. If you would like to make the system a bit more mature, there is an easy method to install all packages with standard priority:

# tasksel install standard

Of course, you can also just use aptitude to install packages individually.

After the installation there will be a lot of downloaded packages in /var/cache/apt/archives/. You can free up some diskspace by running:

# aptitude clean

Create a User

Use the adduser command to create a new user account:

# adduser myusername

You will be prompted for a full name and a password.

The normal Ubuntu configuration is to allow this new user to administer the system using sudo. To set this up, first create an admin group and add your new user to it:

# addgroup --system admin
# adduser myusername admin

You can now use the visudo command to add these lines to the end of /etc/sudoers, so that any user in the admin group can administer the system:

# Members of the admin group may gain root privileges
%admin ALL=(ALL) ALL

If you don't want to follow this configuration, then remember to set a root password:

# passwd root

Install the Ubuntu Desktop

At this point, you probably want to reboot into your new Ubuntu system to make sure it all works. Once you've done that, log in as the user you just created, and run:

 $ sudo tasksel install standard
 $ sudo tasksel install ubuntu-desktop

You will need to enter your password to authorise sudo to run as root.

tasksel will now get on with installing the packages that make up the Ubuntu desktop, which will take a while. When it's finished, you should be presented with a graphical login prompt. The installation is now complete, so go ahead and log in.

[19] These include the GNU core utilities and commands like sed, grep, tar and gzip.