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linux distributions

Open Source Photoshop Software

Q. Is there is a open source Photoshop software for Linux operating system?
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Linux Downloads For Server / Desktop / Laptop Users

I would like to switch to Linux. I want to try free and functional operating system. How do I download Linux ISO images to install on my Desktop / Laptop / Server? Where can I download Linux operating system for my desktop usage?
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How do I enable laptop mode to improve Linux laptop battery life?

Q. I’m using Redhat enterprise Linux desktop / workstation operating system with HP laptop. Several Linux distributions have a / script to enable to disable Laptop mode but Redhat misses the script. How do I enable or disable laptop mode on fly?

A. Modern Linux kernel includes very good support for Laptop mode. It is use to control the IO subsystem. When laptop mode is enabled, the Linux will try to be smart about when to do disk I/O. It gives as much time as possible to be in a low power state. If mode is disabled if value is set to zero (0). To enable mode use non zero value such as 5.

Display or print current Laptop mode

Type the following command:
$ cat /proc/sys/vm/laptop_mode


Turn on or enable Laptop mode

Type the following command as the root user:
$ sudo echo 5 > /proc/sys/vm/laptop_mode
# echo 5 > /proc/sys/vm/laptop_mode

A note about Ubuntu Linux

According to this page:

Ubuntu has a laptop-mode-tools package, which is installed by default on laptops. However, laptop mode is disabled by default in Ubuntu Edgy (6.10), because some people have been experiencing hangups with it on certain laptops (mostly Thinkpads). Until now, nobody has any clue what is happening here. To reenable laptop mode, edit /etc/default/acpi-support and set ENABLE_LAPTOP_MODE=true.

If you want to use the latest version of laptop mode tools, you can use the Debian packages, they are compatible enough to work out-of-the-box on Ubuntu.

A note about Suse Linux

=> Suse Linux comes with powersaved tool, so please ignore above commands for power saving.

Updated for accuracy.

Linux NFS Export / share directory to other UNIX / Linux computer

Q. I’m using CentOS 5 Linux 64 bit version. How do I share directory called /data2 to all other UNIX / Linux computers?

A. NFS (Network file system) is both a protocol and file system for accessing and sharing file systems across a computer network using UNIX and Linux. NFS v4 is used in modern Linux distributions. It offers performance improvements, mandates strong security, and introduces a stateful protocol etc.

How do I export a directory with NFS?

In order to export or share directory called /data2, you need to edit a file called /etc/exports. The file /etc/exports serves as the access control list for file systems which may be exported to NFS clients.:
# vi /etc/exports
Add config directive as follows:
/data2 *(rw,sync)

Each line contains an export point and a whitespace-separated list of clients allowed to mount the file system at that point. Each listed client may be immediately followed by a parenthesized, comma-separated list of export options for that client.


  • rw - Allow both read and write requests on /data2 NFS volume
  • sync - Reply to requests only after the changes have been committed to stable storage

Save and close the file. Restart the nfs service:
# /etc/init.d/nfs restart

NFS client configuration

Client computer need to mount file system using mount command or /etc/fstab file, enter:
# mkdir /mnt/nfs
# mount -t nfs4 nfsserver-name-or-ip:/data2 /mnt/nfs

Read the man page for more configuration options:
$ man exports

Is my hardware compatible with Linux?

Q. After spending last 6 years with Windows, I’m ready to give out Windows XP and move to Linux. Hardware compatibility is particularly important to me. Here is my configuration:
Intel Pentium D 930 CPU
Intel On board display and sound card
2 x 120 GB hard disk
Sony DVD writer
USB Pen and 1.44 MB Floppy etc

I use computer for Internet / Email and OO for document writing. I need system for writing Perl and PHP code.

Is my hardware compatible with Linux? Which Linux distribution is easy to use?

A. Most old and Intel technology should work with Linux. It is hard to guarantee that your hardware will be 100% compatible. The best way to check this is download any one of the available Live CD from the net. Burn the disk and simply boot from Live CD. If everything worked out fine, you can backup all data and install Linux.

I recommend Ubuntu Linux for new users but there are other distros as well. Check out this post about selecting Linux distributions.

Ubuntu Linux Install Oracle Database XE Server

Q. How do I install Oracle Database XE Server on my Ubuntu Linux desktop system?

A. An Oracle database consists of a collection of data managed by an Oracle database management system. You can download Oracle Database XE server for Debian, Mandriva, Novell, Red Hat and Ubuntu Linux distributions. First you need to get databases up and running in order to use Oracle. The Oracle database has had a reputation among new Linux users as difficult to install on Linux systems. Now Oracle Corporation has packaged recent versions for several popular Linux distributions in an attempt to minimize installation challenges beyond the level of technical expertise required to install a database server.

Make sure you have enough disk space and memory

If you have less than 1GB memory run the following commands to create swap space:
$ sudo dd if=/dev/zero of=/swpfs1 bs=1M count=1000
$ sudo mkswap /swpfs1
$ sudo swapon /swpfs1

Debian / Ubuntu Oracle installation

First modify /etc/apt/sources.list file:
$ sudo vi /etc/apt/sources.list
Append following line:
deb http://oss.oracle.com/debian unstable main non-free
Save and close the file. Next import GPG key:
$ wget http://oss.oracle.com/el4/RPM-GPG-KEY-oracle -O- | sudo apt-key add -
Update package database:
$ sudo apt-get update
Finally install Oracle:
$ sudo apt-get install oracle-xe

Reading package lists... Done
Building dependency tree
Reading state information... Done
The following packages were automatically installed and are no longer required:
  linux-headers-2.6.20-15-generic linux-headers-2.6.20-15
Use 'apt-get autoremove' to remove them.
The following extra packages will be installed:
The following NEW packages will be installed:
  libaio oracle-xe
0 upgraded, 2 newly installed, 0 to remove and 2 not upgraded.
Need to get 221MB/221MB of archives.
After unpacking 405MB of additional disk space will be used.
Do you want to continue [Y/n]? y
Get:1 http://oss.oracle.com unstable/non-free oracle-xe [221MB]

Post-install configuration

You must configure Oracle TCP/IP port and other parameters. Simply type the following command:
$ sudo /etc/init.d/oracle-xe configure

Oracle Database 10g Express Edition Configuration
This will configure on-boot properties of Oracle Database 10g Express
Edition.  The following questions will determine whether the database should
be starting upon system boot, the ports it will use, and the passwords that
will be used for database accounts.  Press  to accept the defaults.
Ctrl-C will abort.
Specify the HTTP port that will be used for Oracle Application Express [8080]: [Enter key]
Specify a port that will be used for the database listener [1521]:[Enter key]
Specify a password to be used for database accounts.  Note that the same
password will be used for SYS and SYSTEM.  Oracle recommends the use of
different passwords for each database account.  This can be done after
initial configuration:secret
Confirm the password:secret
Do you want Oracle Database 10g Express Edition to be started on boot (y/n) [y]:y
Starting Oracle Net Listener...Done
Configuring Database...Done
Starting Oracle Database 10g Express Edition Instance...Done
Installation Completed Successfully.
To access the Database Home Page go to ""

To access the Database Home Page go to Open a web browser and type url (you need to use username "system" and password setup earlier)

Ubuntu Linux Install Oracle Database XE Server


Understanding command line shell

Q. I’ve migrated from Windows NT to Linux workstation. Most documents refer to a command line shell. Can you explain me command line shell?

A. A shell allows you to type the commands such as date or clear. There are many shell available. BASH (bourne again shell) is default shell for most Linux distributions.

It also known as a command interpreter which takes command from user and pass the same to kernel for execution. Bash shell supports aliases, filename completion, command history, POSIX compatibility and many other features.

Other UNIX / Linux shell

  • csh / tcsh
  • sh / ksh

Difference Between Linux and UNIX

What is the difference between Linux and UNIX operating systems?
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