linux tips

All new external USB/FireWire disks come formatted as FAT32. The file permissions can get a little messed up, if we use that type of disk for Linux machines. So, there are two things we need to do for any brand new disk: (1) Create a partition (provides a partition table) and (2) format the disk for ext3. An example follows after two important notes…

Before you begin:
Please take note that all of the specific /dev/### device information used in the example will be unique to your machine. Therefore, you should not follow the example verbatim… you’ll need to figure out WHICH device you actually need to partition and format. One way to determine the logical mount point of a new device is to compare what is listed by running ‘df’ or ‘mount’ with what shows up in:
#> cat /proc/diskstats

Also, the new disk that you are formatting SHOULD NOT be mounted to the machine during the format process. It is also necessary to disable fstab-sync prior to formatting to prevent the machine from trying to ‘automount’ the disk during the process.

Disabling fstab-sync:
Follow these steps to disable/enable fstab-sync before/after formatting a new disk:
Disabling…
(1) #> cd /etc/hal/device.d/
(2) #> rm 50-fstab-sync.hal
(3) #> ln -s /bin/false 50-fstab-sync.hal
Enabling…
(1) #> cd /etc/hal/device.d/
(2) #> rm 50-fstab-sync.hal
(3) #> ln -s /usr/sbin/fstab-sync 50-fstab-sync.hal

Format example using fdisk:
Here is an example of how the process works:

#Partition the disk for ext3

[root@linuxtips ~]# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won’t be recoverable.

The number of cylinders for this disk is set to 38913.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0×0000 of partition table 4 will be corrected by w(rite)

Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition’s system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)

Command (m for help): d
No partition is defined yet!

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-38913, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-38913, default 38913):
Using default value 38913

Command (m for help): p

Disk /dev/sdc: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdc1 1 38913 312568641 83 Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

#Format the disk for ext3 using `mkfs`
[root@linuxtips ~]# mkfs -t ext3 /dev/sdc1
mke2fs 1.35 (28-Feb-2004)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
39075840 inodes, 78142160 blocks
3907108 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=79691776
2385 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616

Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.

Firewall
You will need to do a lot of testing with the ‘firewall’ before you may call it good. This is an area that often will cause you problems. If you are using the “ufw firewall” then you will want to enable it first.

$ ufw enable

Linux Terminal Server Firewall (DHCP,SSH, Samba)
You will need to enable several ports for a LTSP server as DHCP on ports 67,68 ,and of course you SSH on port 22.

$ ufw allow 67/udp
$ ufw allow 68/udp
$ ufw allow 445/tcp
$ ufw allow 13/tcp

I tried to install “beryl in my “ubuntu 8.10″….and what i got is…

$ sudo apt-get install beryl-manager
Reading package lists… Done
Building dependency tree
Reading state information… Done
E: Couldn’t find package beryl-manager

I think “Beryl” has been overtaken by “compiz”, and I think “beryl” doesn’t exists any more.
So look for “compizconfig-settings-manager” instead.

If you used Ubuntu Linux for longer than a month, you must have realized that every 30 times you boot up you are forced to run a file system check. This file system check is necessary in order to keep your filesystem healthy. Some people advise turning the check off completely, but that is generally not a recommended solution. Another solution was to increase the number of maximum mounts from 30 to some larger number like 100. That way it’s about 3 times less annoying. But this solution is also not recommended. Enter AutoFsck.

AutoFsck is a set of scripts that replaces the file system check script that comes shipped with Ubuntu. The difference is that AutoFsck doesn’t ruin your day if you are so unfortunate to encounter the 30th mount. The most important difference is that AutoFsck does its dirty work when you shut your computer down, not during boot when you need your computer the most!

The 30th time you mount your filesystem, AutoFsck will wait until you shut down your computer. It will then ask you if it is convenient for you to check your filesystem. If it is convenient for you, then AutoFsck will restart your computer, automatically execute the filesystem check, and then immediately power down your system. If it is not convenient for you to check your filesystem at that moment, then AutoFsck will wait until the next time you shut down your computer to ask you again. Being prompted for a file system check during shutdown is infinitely more convenient than being forced to sit through a 15 minute check during boot up.

So, here’s how you get going with AutoFsck.

* First, you need to download the package. It is available on the project page , but here is a direct link .
* Extract the contents of the archive to anywhere that’s convenient for you.
* Inside that folder, run the script called ‘install’.
* Follow the on-screen instructions.
* AutoFsck will start working immediately.

I haven’t done much reading about whether or not this script will be included in the next release of Ubuntu, but I definitely think it should be. AutoFsck finally makes Ubuntu the ultimate distribution of Linux.

As many visitors have suggested, Bonager is also a good solution for this issue. Bonager sits in your system tray and lets you easily see how many boots you have left until a scan is required. It will warn you if a scan is about to happen, and it also lets you force a scan early if you want to get it out of the way. This solution does not check the filesystem on shutdown like AutoFsck does, so if you’re not paying attention or you forget that a check is coming, you might still be surprised.

Linux LVM partitions do not mount the same way as the ext2 and ext3 partitions that you may be used to. Consider the following example from a dual boot (Windows XP + CentOS) machine:

# fdisk -l /dev/sda

Disk /dev/sda: 750.1 GB, 750156374016 bytes
255 heads, 63 sectors/track, 91201 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sda1 1 6 48163+ de Dell Utility
/dev/sda2 * 7 4510 36178380 7 HPFS/NTFS
/dev/sda3 4511 4771 2096482+ 83 Linux
/dev/sda4 4772 91201 694248975 5 Extended
/dev/sda5 4772 91201 694248943+ 8e Linux LVM

# mount /dev/sda5 /tmp/mnt
mount: /dev/sda5 already mounted or /tmp/mnt busy

Okay, so we need to determine the volume group that contains the physical volume /dev/sda5:

# pvs
PV VG Fmt Attr PSize PFree
/dev/sda5 VolGroup00 lvm2 a- 662.06G 352.00M

Next, we need to list the logical volumes in VolGroup00:

# lvdisplay /dev/VolGroup00
— Logical volume —
LV Name /dev/VolGroup00/LogVol00
VG Name VolGroup00
LV UUID ThdwBX-Vj7g-Z2hE-sPq7-00v3-Pij8-6Kx7UF
LV Write Access read/write
LV Status available
# open 1
LV Size 659.78 GB
Current LE 21113
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:0

— Logical volume —
LV Name /dev/VolGroup00/LogVol01
VG Name VolGroup00
LV UUID Lxe5g6-cdyD-Se9W-FX9g-PqyC-2lI8-zYgDfe
LV Write Access read/write
LV Status available
# open 1
LV Size 1.94 GB
Current LE 62
Segments 1
Allocation inherit
Read ahead sectors 0
Block device 253:1

In this example, we know that /dev/VolGroup00/LogVol00 contains the physical data that we would like to mount. If you are unsure about what to mount on your system, look at the LV Size and compare it to the output from ‘df -h’ (our system output is below):

# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/VolGroup00-LogVol00
650G 306G 312G 50% /
/dev/sda3 2.0G 77M 1.8G 5% /boot
none 1005M 0 1005M 0% /dev/shm

The other logical volume returned from ‘lvdisplay’ in our example is a swap partition, which we do not want to mount. Here is the command for mounting the desired logical volume:

# mount /dev/VolGroup00/LogVol00 /tmp/mnt

Introduction

Ubuntu has a number of applications preinstalled, such as Firefox, Evolution, Open Office and Gimp. This is a pretty complete package, but hey, this is Linux and we want to make our own choices. Fortunately there are more than 24.000 (!) applications and software packages at your disposal.

Perhaps you’re accustomed to installing Windows applications by “simply” manually downloading the installer of an application that you fancy, from some website. In Ubuntu this works differently and even easier. You don’t download anything manually from a website anymore. Instead, you install only from the software repositories of Ubuntu itself. A lot easier, because you don’t have to spend time searching. No more manual downloads!

The advantages: ease and security
The advantages of installing from the repositories are twofold: it’s easy and it’s secure. Not only is the software in the repositories safe, but all applications that you install from them, are being kept safe on your computer by the centralized update function.

The updates from Ubuntu apply not only to Ubuntu itself, but also to all software that has been installed from the repositories!

Two different ways of installing

There are two ways to install an application: through “Add/Remove …” or through “Synaptic Package Manager”.

Installing software is also possible by using the terminal. This third way is less suitable for beginners. So I won’t explain it further here. At the end of this page I’ll explain something about a fourth way: installing manually like in Windows. This fourth way bypasses the inherent security of the repositories and is therefore discouraged.

1. Add/Remove…

By far the easiest way to install applications is this:

1. Establish internet connection.

2. Applications - Add/Remove …

3. Show: “all available applications” (by clicking the arrow next to the box). Now wait a little, because Ubuntu is retrieving new software lists from the internet.

4. In the “Search” box, type the name of the application you want, for example epiphany if you want to install the lightweight web browser Epiphany. Or a descriptive term, like web browser. The search begins automatically, don’t press Enter.

5. Tick the application (in the example: Epiphany web browser) and press the button “Apply changes”.

6. That’s it! Epiphany will be downloaded and installed automatically. A menu item for Epiphany will be added automatically to Applications - Internet.

Note: “Add/Remove…” only gives you access to the most popular applications in the repositories, not to all available applications.

2. Synaptic Package Manager

With Synaptic Package Manager you can install all 24.000 applications that are in the software repositories of Ubuntu.

Synaptic also works with queries, much like you use Google. In order to use it, you need to establish internet connection first.

Synaptic can be used like this: for example, you’re looking for a simple word processor that’s faster than Open Office Writer, but has more features than the simple text editor Gedit. You’ve heard of the application Abiword, and you want to give it a try.

Synaptic can be found under System - Administration - Synaptic Package Manager.

Press the Search button in the toolbar of Synaptic and type abiword in the popup screen.

Press Search in the popup screen.

Synaptic will then present you with a number of software packages that have something to do with Abiword. In most cases you simply choose the package with the most appropriate name, in this case abiword (or abiword-gnome). Notice also the description of the package, which appears below when you click on a package.

Tick abiword (or abiword-gnome) and press the button Apply in the toolbar.

Now Synaptic fetches Abiword from the repositories of Ubuntu, along with the necessary supporting files, and installs it for you. A menu item will be added automatically in Applications - Office.

Easy as can be!

Avoid using it: manual installation

Manual installation, like in Windows, is also possible in Ubuntu. But this is discouraged, because it bypasses the inherent security of the software repositories! Also you won’t have the benefit of the centralized update function, for manually installed software.

For manual installation you’ll need to download an installer with the extension .deb (from Debian: Ubuntu is based on Debian). Simply doubleclick it like you would a Windows installer (.exe) in Windows.

Installers with the extension .rpm (Red Hat Package Management) are useless in Ubuntu: those are installers made for other kinds of Linux distributions that are rpm-based.

You can also manually install Linux software that has no installer. But that’s an awful job and definitely not suitable for beginners.

I bet you Linux people smirked when the Mac OS X guys had to use the command line (possibly for the first time), didn’t you?
Well, if you’re running Linux, I’ll assume that you’re used to the command line, so I won’t feel bad throwing you an archaic series of commands to install all the software you need to be up and running with Rail.

Using a Package Manager

As I mentioned, many Linux distributions come with their own package managers, including apt-get , yum, and rpm, among others.
Of course, you’re free to use the package manager that’s bundled with your Linux distribution to install Ruby, and if you become stuck with the instructions given here for whatever reason, that may be a good option for you.
Rather than attempt to cover all the different package managers available, I’ll show you how to install Ruby the manual way.

Prerequisites

The only prerequisite for installing Ruby on Linux is that you have the gcccompiler installed on your machine. gcc ships with most Linux distributions by default, but if it’s not on your system, you’ll either need to use your system’s package management system to install it (look for “build essential” or “basic compiler”), or to download a native binary for your system.8
Enter the following instructions at the command line to confirm that your compiler is in place:
$ gcc -v
If the version number for the compiler is displayed, as shown in Figure 2.13, you’re ready to install Ruby.

Installing Ruby on Linux

Ruby is available for download from the Ruby ftp site.9 As mentioned at the outset of this chapter, I recommend the use of version 1.8.6 of the Ruby interpreter.
Build Dependencies

Here is a quick tip if you are using a Debian-based Linux distribution-Ubuntu, for example). Before compiling Ruby, make sure you have all the required packages by entering the following command:

$ apt-get build-dep ruby1.8

Download the appropriate tar file for Ruby (this will be named something like ruby1.8.6.tar.gz), and extract the archive using the gunzip and tar commands:

$ gunzip ruby-1.8.6.tar.gz
$ tar xvf ruby-1.8.6.tar
$ cd ruby-1.8.6

Then change into the new directory that was created, From this directory, run the following command to compile and install Ruby in /usr/local:

$ ./configure && make && sudo make install 

This process may take 20 minutes or more, so be patient.
Once it’s completed, you should add /usr/local/bin to your PATHenvironment variable. I’ll assume that, being a Linux user, you know how to do that. Once that environment variable is set, you can enter the following command to check which version of Ruby you installed:

$ ruby -v

The message displayed should confirm that you’re running version 1.8.6

Now, on to the next step: installing RubyGems.

Installing RubyGems on Linux

Next up is the installation of RubyGems, the package manager for Ruby-related software. RubyGems works much like the package manager that your operating system uses to manage the various Linux utilities installed on your machine. RubyGems makes it easy to install all sorts of additional software and extensions for Ruby.
RubyGems is available for download from http://rubyforge.org/projects/rubygems/. Once you’ve downloaded and extracted it, change to the rubygems directory and run the following command:

$ sudo gem update –system

Installing Rails on Linux

Using RubyGems, the installation of Rails itself is a breeze. To install Rails, type the following input at the command prompt as the root user (or using sudo if it’s installed on your system):

$ sudo gem install rails

The process may take ten minutes or so, depending on the speed of your Internet connection, but that’s all you need to do! And as an added bonus, RubyGems gives us an easy way to stay up to date with future Rails releases—whenever we want to upgrade Rails, we just need to type this command!
To confirm that your Rails installation was successful, type the following command to display the version of Rails that was installed:

$ rails -v

 All that’s left now is to install a database—then we can get to work!

Installing SQLite on Linux

Most modern Linux distributions may or may not come packaged with a (more or less) recent version of SQLite and you’re free to use that. It is crucial, however, that you’re installing SQLite 3.x (as opposed to SQLite 2.x).
In case your Linux distribution doesn’t ship with a prepackaged version of SQLite, follow the simple installation instructions found below.
SQLite is available for download from http://www.sqlite.org/download.html. The rest of these instructions assume you download the source tarball. As of this writing, the most recent version of SQLite available was 3.5.4.
Once you have the file, it’s time to extract and compile it using the following batch of commands:

$ tar zxvf sqlite-3.5.4.tar.gz
$ cd sqlite-3.5.4
$ ./configure –prefix=/usr/local
$ make
$ sudo make install

At this point you have successfully installed SQLite on your Linux system. To confirm that, the following command will print out the version of SQLite that you downloaded and installed:

sqlite3 –version

Assuming that you have the directory /usr/local/bin in your operating system PATH.

 Installing the SQLite Database Interface for Ruby

Lastly, we need to install a tiny little module that allows Ruby to talk to SQLite databases. To do so, we’ll use the RubyGems system we’ve installed earlier. Because of that, the installation boils down to a single command only:

sudo gem install sqlite3-ruby

Congratulations, now you’re all done!

of disk for Linux machines, because the file permissions can get a little messed up. So, there are two things we need to do for any brand new disk: (1) Create a partition (provides a partition table) and (2) format the disk for ext3. An example follows after two important notes…

Before you begin:
Please take note that all of the specific /dev/### device information used in the example will be unique to your machine. Therefore, you should not follow the example verbatim… you’ll need to figure out WHICH device you actually need to partition and format. One way to determine the logical mount point of a new device is to compare what is listed by running ‘df’ or ‘mount’ with what shows up in:
#> cat /proc/diskstats

Also, the new disk that you are formatting SHOULD NOT be mounted to the machine during the format process. It is also necessary to disable fstab-sync prior to formatting to prevent the machine from trying to ‘automount’ the disk during the process.

Disabling fstab-sync:
Follow these steps to disable/enable fstab-sync before/after formatting a new disk:
Disabling…
(1) #> cd /etc/hal/device.d/
(2) #> rm 50-fstab-sync.hal
(3) #> ln -s /bin/false 50-fstab-sync.hal
Enabling…
(1) #> cd /etc/hal/device.d/
(2) #> rm 50-fstab-sync.hal
(3) #> ln -s /usr/sbin/fstab-sync 50-fstab-sync.hal

Format example using fdisk:
Here is an example of how the process works:

#Partition the disk for ext3

[root@andrew ~]# fdisk /dev/sdc
Device contains neither a valid DOS partition table, nor Sun, SGI or OSF disklabel
Building a new DOS disklabel. Changes will remain in memory only,
until you decide to write them. After that, of course, the previous
content won’t be recoverable.

The number of cylinders for this disk is set to 38913.
There is nothing wrong with that, but this is larger than 1024,
and could in certain setups cause problems with:
1) software that runs at boot time (e.g., old versions of LILO)
2) booting and partitioning software from other OSs
(e.g., DOS FDISK, OS/2 FDISK)
Warning: invalid flag 0×0000 of partition table 4 will be corrected by w(rite)

Command (m for help): m
Command action
a toggle a bootable flag
b edit bsd disklabel
c toggle the dos compatibility flag
d delete a partition
l list known partition types
m print this menu
n add a new partition
o create a new empty DOS partition table
p print the partition table
q quit without saving changes
s create a new empty Sun disklabel
t change a partition’s system id
u change display/entry units
v verify the partition table
w write table to disk and exit
x extra functionality (experts only)

Command (m for help): d
No partition is defined yet!

Command (m for help): n
Command action
e extended
p primary partition (1-4)
p
Partition number (1-4): 1
First cylinder (1-38913, default 1): 1
Last cylinder or +size or +sizeM or +sizeK (1-38913, default 38913):
Using default value 38913

Command (m for help): p

Disk /dev/sdc: 320.0 GB, 320072933376 bytes
255 heads, 63 sectors/track, 38913 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes

Device Boot Start End Blocks Id System
/dev/sdc1 1 38913 312568641 83 Linux

Command (m for help): w
The partition table has been altered!

Calling ioctl() to re-read partition table.
Syncing disks.

#Format the disk for ext3 using `mkfs`
[root@linuxtips ~]# mkfs -t ext3 /dev/sdc1
mke2fs 1.35 (28-Feb-2004)
Filesystem label=
OS type: Linux
Block size=4096 (log=2)
Fragment size=4096 (log=2)
39075840 inodes, 78142160 blocks
3907108 blocks (5.00%) reserved for the super user
First data block=0
Maximum filesystem blocks=79691776
2385 block groups
32768 blocks per group, 32768 fragments per group
16384 inodes per group
Superblock backups stored on blocks:
32768, 98304, 163840, 229376, 294912, 819200, 884736, 1605632, 2654208,
4096000, 7962624, 11239424, 20480000, 23887872, 71663616

Writing inode tables: done
Creating journal (8192 blocks): done
Writing superblocks and filesystem accounting information: done

This filesystem will be automatically checked every 36 mounts or
180 days, whichever comes first. Use tune2fs -c or -i to override.

Hello guys,

you can change the default backgourd pictures…..like this..

$sudo  gedit  ‘/usr/share/gnome-background-properties/ubuntu-wallpapers.xml’

my file looks like this..

<?xml version=”1.0″ encoding=”UTF-8″?>
<!DOCTYPE wallpapers SYSTEM “gnome-wp-list.dtd”>
<wallpapers>
<wallpaper>
<name>ubuntu </name>
<filename>/usr/share/backgrounds/warty-final-ubuntu.png </filename>
<options> zoom </options>
<pcolor> #8f4a1c </pcolor>
<scolor> #8f4a1c </scolor>
<shade_type>solid </shade_type>
</wallpaper>
<wallpaper>
<name> img1 </name>
<filename> /usr/share/backgrounds/img1.png </filename>
<options> zoom </options>
<pcolor> #8f4a1c </pcolor>
<scolor> #8f4a1c </scolor>
<shade_type> solid </shade_type>
</wallpaper>
<wallpaper>
<name> img2 </name>
<filename> /usr/share/backgrounds/img2.png </filename>
<options> zoom </options>
<pcolor> #8f4a1c </pcolor>
<scolor> #8f4a1c </scolor>
<shade_type>solid</shade_type>
</wallpaper>
<wallpaper>
<name>img3</name>
<filename>/usr/share/backgrounds/img3.png</filename>
<options>zoom</options>
<pcolor>#dab082</pcolor>
<scolor>#dab082</scolor>
<shade_type>solid</shade_type>
</wallpaper>
<wallpaper>
<name>img4</name>
<filename>/usr/share/backgrounds/img4.jpg</filename>
<options>zoom</options>
<pcolor>#8f4a1c</pcolor>
<scolor>#8f4a1c</scolor>
<shade_type>solid</shade_type>
</wallpaper>
<wallpaper>
<name>img5</name>
<filename>/usr/share/backgrounds/img5.jpg</filename>
<options>zoom</options>
<pcolor>#8f4a1c</pcolor>
<scolor>#8f4a1c</scolor>
<shade_type>solid</shade_type>
</wallpaper>
<wallpaper>
<name>img6</name>
<filename>/usr/share/backgrounds/img6.jpg</filename>
<options>zoom</options>
<pcolor>#8f4a1c</pcolor>
<scolor>#8f4a1c</scolor>
<shade_type>solid</shade_type>
</wallpaper>
<wallpaper>
<name>img7</name>
<filename>/usr/share/backgrounds/img7.jpg</filename>
<options>zoom</options>
<pcolor>#8f4a1c</pcolor>
<scolor>#8f4a1c</scolor>
<shade_type>solid</shade_type>
</wallpaper>
<wallpaper>
<name>img8</name>
<filename>/usr/share/backgrounds/img8.jpg</filename>
<options>zoom</options>
<pcolor>#8f4a1c</pcolor>
<scolor>#8f4a1c</scolor>
<shade_type>solid</shade_type>
</wallpaper>
<wallpaper>
<name>opera</name>
<filename>/usr/share/backgrounds/opera.jpg</filename>
<options>zoom</options>
<pcolor>#8f4a1c</pcolor>
<scolor>#8f4a1c</scolor>
<shade_type>solid</shade_type>
</wallpaper>
</wallpapers>

add more backgourds as you like…k

enjoy..