Bandwidth Measurement Manually

It seems the command line "scp" can we use to check the real bandwidth. For example, I will measure the bandwidth from my place to Internet Exchange. At my place, I use a computer "ppin-msmunir2". At Internet Exchange, I use a computer with the IP Address 202.46.2.222. This is the result after running the command "scp" or Secure Copy.

Code :

msmunir@ppin-msmunir2:~ # scp VirtualBox-2.1.2_41885_fedora9-1.i386.rpm
msmunir@202.46.3.98:/var/www/html/download/.
msmunir@202.46.3.98's password:
VirtualBox-2.1.2_41885_fedora9-1.i386.rpm 100% 15MB 25.4KB/s 10:00
msmunir@ppin-msmunir2:~ #

Note :

VirtualBox-2.1.2_41885_fedora9-1.i386.rpm = file that will be send
msmunir@202.46.3.98:/var/www/html/download/ = my account at remote computer and plus with location where the file will be places.

You see, a file with size of 15 MB be transfered with rate 25.4 KB/s and need time for 10 minutes. If we converte, 25.4 KB/s is equal to 203.2 Kb/s. Therefore, the bandwitdh beetwen my place to Internet Exchange is 25.4 KB/s or 203.2 Kb/s.

by.msmunir@batan.go.id
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How to format USB FlashDisk

Sometime you need to format your USB FlashDisk. To do that, follow these steps :

1.Plug in your USB FlashDisk into USB port on your Linux computer

2.Open the terminal

3.Un mount the USB FlashDisk


Code :
# umount /media/MSMUNIR5/

4.Determine USB FlashDisk's device address

Code :
# fdisk -l

Based on this information, we know that the USB Flash Disk has a device address /dev/sdb1. You can check the capacity.

5.Now, you can format your USB FlashDisk or /dev/sdb1. And give the new name such as “MSMUNIR9”.

Code :
# mkfs.vfat -F 32 -n MSMUNIR9 -I /dev/sda

6.Unplug USB FlashDisk and plug again. Check the label name.

by. msmunir@batan.go.id

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Join Files on Linux System

After you understood how to split a file, now I will show you how to join the files. Suppose you have files like this :

Warrior_of_The_Net.01
Warrior_of_The_Net.02
Warrior_of_The_Net.03
...
Warrior_of_The_Net.15

And you want to join become a file has name “Warrior_of_The_Net.mpg”. To do this, write down this command line :

Code :
$ cat Warrior_of_The_Net.01 Warrior_of_The_Net.02
Warrior_of_The_Net.03 Warrior_of_The_Net.04 Warrior_of_The_Net.05
Warrior_of_The_Net.06 Warrior_of_The_Net.07 Warrior_of_The_Net.08
Warrior_of_The_Net.09 Warrior_of_The_Net.10 Warrior_of_The_Net.11
Warrior_of_The_Net.12 Warrior_of_The_Net.13 Warrior_of_The_Net.14
Warrior_of_The_Net.15 > Warrior_of_The_Net.mpg

Write down all script above on one line.

The different between HJSplit 1.4 for Windows and “cat” tool, is you just mark all files. You do not necessary to write all files name one by one.

by.msmunir@batan.go.id
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Split File on Fedora Linux System

On other article, I mention before that you can split file with HJSplit 1.4 for Windows. Actually, Fedora had has tool to split file. For instance, I have a big file “Warrior_of_The_Net.mpg” with size 148 MB. Now, I will split it into small ones, say 9.6MB or 10.000.000 B each.

Code :
$ split -d -b 10000000 Warrior_of_The_Net.mpg Warrior_of_The_Net.


Note :
split = the command line
-d and -b 10000000 = option, -d is numeric suffixes and -b is output size in byte
Warrior_of_The_Net.mpg = input file
Warrior_of_The_Net. = output file name, with dot at the end of output file name

The output files are :
Warrior_of_The_Net.01
Warrior_of_The_Net.02
Warrior_of_The_Net.03
...
Warrior_of_The_Net.15

If you want the output file has name like Warrior_of_The_Net.001, you can use sintax like this :

Code :
$ split -d -b 10000000 Warrior_of_The_Net.mpg Warrior_of_The_Net.0


To join the files, please use “cat” command line.

By. Muh. Sirojul Munir (msmunir@batan.go.id)
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wget on FreeBSD

If you are coming from Linux, you will find wget missing on FreeBSD. Many programs that relay on wget will stop working on FreeBSD.

For downloading files, FreeBSD use "fetch". To download a file with fetch use

# fetch http://bizhat.com/game.zip


If you really need wget working, you can do one of the following, first method is symlink. Today i was installing qmail-ldap, the instruction says wget, i have changed it to fetch and executed and it worked fine. So i though of a symlink, that will do the same with out changing wget to fetch or installing wget on FreeBSD.

# ln -s /usr/bin/fetch /usr/bin/wget

Now every call to wget will invoke fetch. You can install wget on FreeBSD from ports or even download the source and compile it your self. To install wget from ports, do the following.

# cd /usr/ports/ftp/wget
# make install clean
# rehash

Now you have wget installed on your FreeBSD server. I recommend using fetch with symlink as both wget and fetch do the same job.

Sumber : http://www.scriptinstallation.in/wget_fetch_freebsd.html

by.msmunir@batan.go.id
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Making MTRG Agent on Fedora Linux System

MRTG is one of few tools to monitor your network traffic or your computer activities. MRTG is a X-Y graphic as function of time vs baud rate or speed in Byte per second. In this tutorial, suppose you had MRTG Server. I just want to set up MRTG Agent only on my computer based on distro Fedora 9.

Follow these steps :

1. Edit MRTG Agent configuration file and then restart the application.
# mcedit /etc/snmp/snmpd.conf
# /etc/rc.d/init.d/snmpd restart


2. Test your snmpd have run or not. These testing can be done from local (MRTG Agent) or remote machine (MRTG Server).
# snmpget -v 1 -c public 202.46.3.114 1.3.6.1.2.1.1.1.0
# snmpwalk -v 1 -c public 202.46.3.114 system
# snmpwalk -v 1 -c public 202.46.3.114 IP-MIB::ipAdEntIfIndex
Another testing :
# nmap 202.46.3.114
# iptables --list

3. Create configuration file on MRTG Server
# cfgmaker public@202.46.3.114 > psjumat2.cfg
or
# cfgmaker --global "workdir: /opt/lampp/htdocs/mrtg" -ifref=ip --output /etc/mrtg/psjumat2.cfg --global 'options[_]: growright,bits' public@202.46.3.114

4. Create HTML file.
# indexmaker --output=/opt/lampp/htdocs/mrtg/psjumat2.html /etc/mrtg/psjumat2.cfg
Actually, you can change psjumat2.html become index.html

5. Create mechanism to get data from MTRG Agent with automatically.
# mrtg -c /etc/mrtg/psjumat2.cfg
or
# env LANG=C /usr/bin/mrtg /etc/mrtg/psjumat2.cfg

6. To make your SNMPD automatically run every Start-up of your computer, please add a command line to /etc/rc.local :
# echo "/usr/sbin/snmpd -c /etc/snmp/snmpd.conf" >> /etc/rc.local

7. Create mechanism to get data from MRTG Agent periodically, such as every 5 minutes. To do this, you must add new line at the end of /etc/cron.d/mrtg file like this :

*/5 * * * * root LANG=C LC_ALL=C /usr/bin/mrtg /etc/mrtg/psjumat2.cfg

by.msmunir@batan.go.id
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Change the Linux Prompt

To make your Linux prompt more informative, you need to change your Linux prompt. Suppose, you want to change your prompt like this :

-bash-3.2#

Become like this :

root@ppin-msmunir2:~ #

This prompt give more informations such as who are you, where you are, what is your level, and so on. It's easy to do that, just add one line below on the end of /etc/profile file.

Code :

export PS1="\u@\h:\w # "

Or, your prompt become like this :

[root@ppin-msmunir2:~ ] #

Just add one line below on the end of /etc/profile file

Code :

export PS1="[\u@\h:\w ] # "

Others sintax :

$ PS1="\h>" --> show hostname dan character >

$ PS1="\u~" --> show recent user and character ~

$ PS1="\W" --> show current directory

$ PS1="\u@\h" --> show user, "@", and hostname

Read More......

Change Hostname on Fedora 9 (Linux System)

The prompt before setting
Code :
[msmunir@localhost home]$ uname -a
Linux localhost.localdomain 2.6.15-1.2054_IGN1 #1 Fri Jun 30 10:01:26 WIT 2006 i686
i686 i386 GNU/Linux
[msmunir@localhost home]$


See the content of /etc/hosts file :

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
::1 localhost.localdomain localhost
202.46.3.114 psjumat2.batan.go.id psjumat2


Or you can see another sample of /etc/hosts file :

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost psjumat2
::1 localhost.localdomain localhost psjumat2

Another example

# Do not remove the following line, or various programs
# that require network functionality will fail.
127.0.0.1 localhost.localdomain localhost
::1 localhost6.localdomain6 localhost6
202.46.3.98 psjumat2 psjumat psjumat2.batan.go.id

Based on these examples, you make many alias, such as psjumat, psjumat2 or psjumat2.batan.go.id.

Restart your named service
Code :
[root@localhost etc]# /etc/rc.d/init.d/named restart
Stopping named: [FAILED]
Starting named: [ OK ]
[root@localhost etc]#

Reboot your host
Code :
[root@localhost etc]# reboot

After reboot, prompt has changed like this
Code :
[msmunir@psjumat4 ~]$ uname -a
Linux psjumat4.batan.go.id 2.6.15-1.2054_IGN1 #1 Fri Jun 30 10:01:26 WIT 2006 i686
i686 i386 GNU/Linux
[msmunir@psjumat4 ~]$

Compare with the beginning of prompt.

by.msmunir@batan.go.id
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Merge PDF Files on Fedora Linux

To merge or combine two PDF files or more, you can use ghostscript command line, without use a Adobe Proffesional. With GhostScript, merge more easy. To do that, you must have ghostscript on your linux. If you don't have it, please run this command line :

Code:

# yum install ghostscript

Example :

You have two PDF files, say first.pdf and second.pdf. And you want to combine become a PDF file, say firstANDsecond.pdf. Place these 2 PDF files on same folder. And now you run :

Code (in one line and case sensitive):

$ ghostscript -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=firstANDsecond.pdf -dBATCH first.pdf second.pdf

or

Code (in one line and case sensitive):

$ gs -dNOPAUSE -sDEVICE=pdfwrite -sOUTPUTFILE=firstANDsecond.pdf -dBATCH first.pdf second.pdf

To merge PDF files, you can use another tool : convert.

Code :

$convert first.pdf second.pdf output.pdf

where first.pdf and second.pdf are the source files, and output.pdf is the destination file.

The difference beetwen “convert” and “gs” tool is on the size of the output file. Based on my test, output file from “gs” tool is 595 kB. Output file from “convert” file is 4.6 MB.

Let's enjoy it.

Muh. Sirojul Munir (msmunir@batan.go.id)

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Anti Spam with Spamassasin on FreeBSD Linux

If we talk about a packet or application or program on Linux system, we talk about 4 things. How to install it, how to configure it, how to start/stop it, and how to know about the status. The same condition for Spamassasin packet. Now, we talk about Spamassasin on FreeBSD system. Suppose, the packet was installed and configured. We just want to know about the status and how to start or stop it.

Viewing the status

Code :

# ps -aux | grep spamd

Example :

[root@serpong4] /usr/local/etc/rc.d # ps -aux | grep spamd

root 79133 2.2 2.2 49588 46956 ?? S 3:34AM 0:52.66 spamd child (perl5.8.8)

root 79123 0.0 1.7 38336 36148 ?? Ss 3:33AM 0:02.14 /usr/local/bin/spamd -m 10 -d
-r /var/run/spamd/spamd.pid

root 79134 0.0 2.0 45216 42628 ?? S 3:34AM 0:19.62 spamd child (perl5.8.8)

root 82056 0.0 0.2 5900 3728 p0 RV+ 4:21AM 0:00.00 grep spamd (csh)

[root@serpong4] /usr/local/etc/rc.d #

Information above show you that the spamassasin is running. If you don't see display like above, it's better to start or restart ke daemon. Start and restart command has difference effect. Restart command will give you the last status of spam daemon.

How to start the spam daemon

Code :

# /usr/local/etc/rc.d/sa-spamd start

or

/usr/local/etc/rc.d # ./sa-spamd start

Example :

[root@serpong4] /usr/local/etc/rc.d # ./sa-spamd restart

spamd not running? (check /var/run/spamd/spamd.pid).

Starting spamd.

[root@serpong4] /usr/local/etc/rc.d #

You see, "spamd not running?" has mean that spamd has stopped. Therefor, it's better to use restart command than start command.

by. Muh. Sirojul Muniri(msmunir@batan.go.id)

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SSH without Password, a Simple Way

Send key pairing to remote computer

Code :

[msmunir@msmunir1 ~]$ cd .ssh

[msmunir@msmunir1 .ssh]$ scp id_rsa.pub
msmunir@202.46.3.66:/home/msmunir/.ssh/id_rsa.pub.lenovo

msmunir@202.46.3.66's password:


id_rsa.pub 100% 410 0.4KB/s 00:00

[msmunir@msmunir1 .ssh]$



Edit "authorized_keys" file on remote computer

Code :

[msmunir@msmunir1 .ssh]$ ssh msmunir@202.46.3.66

msmunir@202.46.3.66's password:

Last login: Sun Jan 25 22:33:30 2009 from 125.160.107.126

msmunir@serpong5:~ # cd .ssh

msmunir@serpong5:~/.ssh # more id_rsa.pub.lenovo

ssh-rsa
AAAAB3NzaC1yc2EAAAABIwAAAQEA1nqwTFg3IoUoUdyAQ65R+26ipEX42L7C3NcBcYEEtY78

lT/qeSaPIPGyfiMXCOeGtghQ12Msrflott+AblAxizERwvNPjeI0DcxSXTbE15R7M5SjOSSKz1wCIyBi

IK5Bi5iIY36K3wqoGSfkekcbtGQKbf+vftwtlsTdrXVO0WMPxoTwJBNGxgljT45JaGyM7KiZpWMFTPBo

jGOiMJY6xV416ZnFlxpKUIMyoKvlysefxI3bw2LnbcDswadpYJInGfqp9pywaMPoA976C43dkmimTLfs

juTFHWSlv8AS4QWuMFev72y9vGVoZ21Fc0dSE3WJ7ovT7d14G6Tf75tBrw==
msmunir@msmunir1.ba

tan.go.id

msmunir@serpong5:~/.ssh #



Block this content of "id_rsa.pub.lenovo" file, then Copy and paste to "authorized_keys" file.


Code :
msmunir@serpong5:~/.ssh # mcedit authorized_keys

Paste with "Ctr-Sht-V" button, edit to make 6 lines become 1 line. Save with F2 and Quit with F10.


Now, you can SSH without password.

By. Muh. Sirojul Munir (msmunir@batan.go.id)

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Making MP3 from CD Audio on Linux, a simple way

1.Insert your CD Audio

2.Ripping your CD Audio to temp folder. Ripping can be done at once

Code :

[msmunir@msmunir1 temp]$ cdparanoia -B


3.See the results of ripping

Code :

[msmunir@msmunir1 temp]$ ls -l


4.Encoding from WAV to MP3. Encoding can not be done at once, one by one

Code :

[msmunir@msmunir1 temp]$ lame track01.cdda.wav 01_song_title.mp3

[msmunir@msmunir1 temp]$ lame track02.cdda.wav 02_song_title.mp3

and so, until all WAV files is encoded.

5.Don't forget to delete WAV files.

Code :

[msmunir@msmunir1 temp]$ rm -f *.wav



See : article "How to encoding WAV to MP3 simultanously"

by."Muh. Sirojul Munir"

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DNS Settings in FreeBSD 6.1 Linux

Actually, this tutorial just for add new hosts or servers into DNS Server based on FreeBSD 6.1 Linux. The DNS Server itself has installed and running well. In this example, I want to add 2 hosts with different name server, that are :
1.dl1.batan.go.id for IP Address 202.46.3.77
2.mrtg.batan.go.id for IP Address 202.46.3.71

The steps are :
1. Edit /etc/namedb/master/batan.go.id file.

Code :
# vi /etc/namedb/master/batan.go.id

Add 2 lines below on that file :
mrtg IN A 202.46.3.71
dl1 IN A 202.46.3.77

2. Restart named


Code :
# /etc/rc.d/named restart

3. Testing

From DNS Server :
Code :
# nslookup
> mrtg
Server: 202.46.2.222
Address: 202.46.2.222#53

Name: mrtg.batan.go.id
Address: 202.46.3.71
> dl1
Server: 202.46.2.222
Address: 202.46.2.222#53

Name: dl1.batan.go.id
Address: 202.46.3.77

From Client :
You can make another testing from Client with web browser. Enter address below for
testing on your address bar.
1.http://mrtg.batan.go.id/
2.ftp://dl1.batan.go.id/

Another testing from client, you can use PING to the hosts.

Regards,
Muh. Sirojul Munir (msmunir@batan.go.id)

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Minicom, a Hyper Terminal for Linux

With minicom, you can access device with RS232 port, such as cisco router and cisco catalyst. To access cisco devices from console port, you must prepared roll-over cable with DB9/DB25 and RJ45 connector on both ends.

Installation :
Code :
# yum install minicom

Setting and configuration.
Code :
-bash-3.2# minicom -s


You must set :
1.Filenames and paths
A - Download directory : /home/msmunir
B - Upload directory : /home/msmunir
C – Script direcory : /home/msmunir
Others let default. To change Download directory, just press A. To exit, press Enter.

2.Serial port setup
A - Serial Device : /dev/ttyS0, awalnya /dev/modem. TtyS0 adalah COM1
E – Bps/Par/Bits : 9600 8N1
Others let default.

3.Save setting, choose menu “Save setup as dfl”

4.Exit from setting, choose menu “Exit from Minicom”


Running Minicom (should be root) :
-bash-3.2# minicom

To exit from Minicom, press Ctr-A X

by.msmunir@batan.go.id

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How to encoding WAV to MP3 simultanously

As I told before, to encode or convert from WAV to MP3 file, you must do that one by one. With the certain script, this encoding can do with simultanously. To do this, make a script, call it "encoding.sh". The content of this file is :


#!/bin/sh


lame track01.cdda.wav track01.mp3

lame track02.cdda.wav track02.mp3

lame track03.cdda.wav track03.mp3

lame track04.cdda.wav track04.mp3

lame track05.cdda.wav track05.mp3

lame track06.cdda.wav track06.mp3

lame track07.cdda.wav track07.mp3

lame track08.cdda.wav track08.mp3

lame track09.cdda.wav track09.mp3

lame track10.cdda.wav track10.mp3

lame track11.cdda.wav track11.mp3

lame track12.cdda.wav track12.mp3

lame track13.cdda.wav track13.mp3

lame track14.cdda.wav track14.mp3

lame track15.cdda.wav track15.mp3

lame track16.cdda.wav track16.mp3

Don't forget to change “encoding.sh” file mode to 777.

Code :

# chmod 777 encoding.sh

I make the script until track #16, because the maximum songs on CD Audio that I have is 16 songs. If the song on a CD Audio only 10 songs, this script still working properly. But if the songs on CD Audio more than 16, you just add command line at the end of “encoding.sh” file, like :

lame track17.cdda.wav track17.mp3

lame track18.cdda.wav track18.mp3

and so on.

To convert all WAV files to MP3 files, you just run :

Code :

# ./encoding.sh

by.msmunir@batan.go.id

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Split File with HJSplit 1.4 for Windows 95 on Fedora 9

If you have a big file and you want to split it become many files, you can try tool like HJSplit 1.4 for Windows 95 (See http://www.freebyte.com/hjsplit/). Although this tool for Windows, you can run it on Linux if you have installed Wine packet.

Example:
I want split my file “Warriors of The Net.mpg” (147.7 MB) to become many files.


The steps :
Open Nautilus, double click hjsplit.exe -> choose “Split” button -> click “File to split” box -> find your a file and click Open -> fill “Split file size (Kb)” box with 10000 -> click “Start” button -> wait until message “Splitting completed” appear -> OK -> Close -> Exit

The result are :
1.Warriors of The Net.mpg.001 (9.8 MB)
2.Warriors of The Net.mpg.002 (9.8 MB)
3.Warriors of The Net.mpg.003 (9.8 MB)
4.Warriors of The Net.mpg.004 (9.8 MB)
5.Warriors of The Net.mpg.005 (9.8 MB)
6.Warriors of The Net.mpg.006 (9.8 MB)
7.Warriors of The Net.mpg.007 (9.8 MB)
8.Warriors of The Net.mpg.008 (9.8 MB)
9.Warriors of The Net.mpg.009 (9.8 MB)
10.Warriors of The Net.mpg.010 (9.8 MB)
11.Warriors of The Net.mpg.011 (9.8 MB)
12.Warriors of The Net.mpg.012 (9.8 MB)
13.Warriors of The Net.mpg.013 (9.8 MB)
14.Warriors of The Net.mpg.014 (9.8 MB)
15.Warriors of The Net.mpg.015 (9.8 MB)
16.Warriors of The Net.mpg.016 (1.2 MB)

I try another split file size such as : 100000, 50000, 40000, 30000, 20000, and 15000. All of these value is invalid. I don't know why?

How to joint files?

Basically, its same method with split file. Follow this steps :

Open Nautilus, double click hjsplit.exe -> choose “Join” button -> click “File to join” box -> find your a main file and click Open -> click “Start” button -> wait until message “Joining completed” appear -> OK -> Close -> Exit

Main file usually is ended with 001, such as “Warriors of The Net.mpg.001”.

by. msmunir@batan.go.id

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Download YouTube Videos without Software

Open 2 windows simultanously :
1.YouTube Video itself, such as : http://www.youtube.com/watch?v=chOS6ssfA0U
2.Download tool, suc as : http://www.techcrunch.com/get-youtube-movie/ or http://www.savevideodownload.com/download.php

The steps :
1.In YouTube windows, open the video that you want to download and copy the address bar.
Example :
http://www.youtube.com/watch?v=chOS6ssfA0U

2.Bring this address to download tool (http://www.techcrunch.com/get-youtube-movie/) and paste this address to “Enter YouTube URL: “ box. Then click “Get Video” button.
3.Right click “Download Link” and choose “Save Link As...”.
4.Change get_video with name you prefer and add extention “.flv”, then click “Save” button.
5.Wait until download finish.

Another method to download YouTube video :
1.Copy the web browser cache related with the video, and rename it to something dot flv.
2.Use download software, such as : Free YouTube Download from http://www.dvdvideosoft.com/


This tutorial just for education only. We do not responsible for out law purposes.
by. msmunir@batan.go.id

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SQL Injection

To check out your database system is secure or not, you can try this testing below. We call it 'SQL Injection' testing. This method will try to enter the system without knowing the username and password. Just use magic string. Try this :

1.Enter phrase 'or''=' for username and password
2.Enter phrase ' or 1=1--' for username and password
3.Enter phrase 'or''=' for username and empty password
4.Enter phrase John'-- for username and phrase 'or''=' for password


How to protect from these method? Basically you just permit characters A to Z, a to z and 0 to 9 only for username and password.
by. msmunir@batan.go.id
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Missing Root Password on Linux

Someday, you must be miss the root password on your computers. You don't need to panic. Keep cool. It's easy to recover the root password. Follow these steps below. You do all these on computer console, you can't do this with remotely.

Steps :
1.Reboot the machine. When linux countdown, immediately press any key until GRUB menu appear.
2.After the GRUB menu appear, press 'e' or edit, and you will see the screen like this :
root (hd0,0)
kernel /vmlinuz-2.6.27.12-78.2.8.fc9.i686 ro root=/dev/VolGroup00/Log
initrd /initrd-2.6.27.12-78.2.8.fc9.i686.img

3.Choose the second line and press 'e' or edit and you will see the screen like this :


4.Replace 'rhgb quite' with 'single', and pres 'b' or boot.


5.Wait until booting process is complete. When prompt # show up, you can change the root password.
[root@msmunir1 /]# passwd
Changing password for user root
New UNIX password:
Retype new UNIX password:
passwd: all authentication tokens updated successfully.
[root@msmunir1 /]#

6.Reboot the machine
[root@msmunir1 /]# reboot

This procedure can use to change another user password.
Read More......

Changing The Desktop Background in Fedora 9

Actually, change the background image is very easy. You just right click on desktop, than choose "Change Desktop Background" option. For detail, see below :

Right click your desktop -> choose "Change Desktop Background" option -> wait until window "Appearance Preferences" appear -> choose tab "Background" -> choose a picture as you like on Wallpaper -> Close.

Beside you can choose a picture for your desktop background, you can choose others like style, colors, theme, etc. Style has 5 options : Centered, Fill screen, Scaled, Zoom, and Tiled. Color has 3 options : Solid color, Horizontal gradient, and Vertical gradient.

If you have a nice picture, and you want to make it become your desktop background, you can use above steps to do that. You just add the files into a folder /usr/share/backgrounds/.

Just for information, the content of this folder and sub folder are :

[root@msmunir1 backgrounds]# ls -l -R -h /usr/share/backgrounds/
/usr/share/backgrounds/:
total 20K
drwxr-xr-x 3 root root 4,0K 2009-01-25 07:48 images
drwxr-xr-x 2 root root 4,0K 2008-12-26 17:49 nature
drwxr-xr-x 2 root root 4,0K 2008-12-26 17:49 tiles
drwxr-xr-x 2 root root 4,0K 2008-12-26 17:49 translucent
drwxr-xr-x 2 root root 4,0K 2009-01-25 08:52 waves

/usr/share/backgrounds/images:
total 1,5M
drwxr-xr-x 2 root root 4,0K 2008-12-26 17:49 branded
-rw-rw-r-- 1 msmunir msmunir 29K 2009-01-25 07:44 default-5_4.png
-rw-rw-r-- 1 msmunir msmunir 29K 2009-01-25 07:45 default.jpg
-rw-rw-r-- 1 msmunir msmunir 29K 2009-01-25 07:45 default.png
-rw-rw-r-- 1 msmunir msmunir 29K 2009-01-25 07:45 default-wide.png
-rw-r--r-- 1 root root 543K 2006-09-06 22:35 earth_from_space.jpg
-rw-r--r-- 1 root root 324K 2006-09-06 22:35 flowers_and_leaves.jpg
-rw-r--r-- 1 root root 206K 2006-09-06 22:35 ladybugs.jpg
-rw-r--r-- 1 root root 183K 2006-09-06 22:35 stone_bird.jpg
-rw-r--r-- 1 root root 75K 2006-09-06 22:35 tiny_blast_of_red.jpg

/usr/share/backgrounds/images/branded:
total 472K
-rw-r--r-- 1 root root 465K 2008-03-10 11:36 GNOME-Curves.png

/usr/share/backgrounds/nature:
total 636K
-rw-r--r-- 1 root root 80K 2008-03-10 11:36 FreshFlower.jpg
-rw-r--r-- 1 root root 180K 2008-03-10 11:36 GreenMeadow.jpg
-rw-r--r-- 1 root root 362K 2008-03-10 11:36 OpenFlower.jpg

/usr/share/backgrounds/tiles:
total 1,7M
-rw-r--r-- 1 root root 4,6K 2006-09-06 22:35 3dgreen.png
-rw-r--r-- 1 root root 50K 2006-09-06 22:35 All-Good-People-1.jpg
-rw-r--r-- 1 root root 20K 2006-09-06 22:35 bark.png
-rw-r--r-- 1 root root 5,4K 2006-09-06 22:35 Blkmarble.jpg
-rw-r--r-- 1 root root 84K 2006-09-06 22:35 blobl.png
-rw-r--r-- 1 root root 11K 2006-09-06 22:35 blue_gray_rough.png
-rw-r--r-- 1 root root 32K 2006-09-06 22:35 bluemars.png
-rw-r--r-- 1 root root 1,7K 2006-09-06 22:35 blue.png
-rw-r--r-- 1 root root 263 2006-09-06 22:35 blue_ridge.png
-rw-r--r-- 1 root root 11K 2006-09-06 22:35 blue_type.png
-rw-r--r-- 1 root root 24K 2006-09-06 22:35 bricks.png
-rw-r--r-- 1 root root 11K 2006-09-06 22:35 brushed_metal.png
-rw-r--r-- 1 root root 18K 2006-09-06 22:35 burlwood.png
-rw-r--r-- 1 root root 29K 2006-09-06 22:35 camouflage.png
-rw-r--r-- 1 root root 20K 2006-09-06 22:35 Chicken-Songs-2.jpg
-rw-r--r-- 1 root root 4,3K 2006-09-06 22:35 Circuit.jpg
-rw-r--r-- 1 root root 13K 2006-09-06 22:35 circuit.png
-rw-r--r-- 1 root root 3,1K 2006-09-06 22:35 clouds.png
-rw-r--r-- 1 root root 9,9K 2006-09-06 22:35 clover.png
-rw-r--r-- 1 root root 21K 2006-09-06 22:35 cork.png
-rw-r--r-- 1 root root 4,7K 2006-09-06 22:35 countertop.png
-rw-r--r-- 1 root root 131K 2006-09-06 22:35 default_blue.jpg
-rw-r--r-- 1 root root 1,8K 2006-09-06 22:35 diffraction-patterns.png
-rw-r--r-- 1 root root 922 2006-09-06 22:35 dots.png
-rw-r--r-- 1 root root 17K 2006-09-06 22:35 dunes.png
-rw-r--r-- 1 root root 28K 2006-09-06 22:35 fibers.png
-rw-r--r-- 1 root root 246 2006-09-06 22:35 fish.png
-rw-r--r-- 1 root root 29K 2006-09-06 22:35 fleur_de_lis.png
-rw-r--r-- 1 root root 72K 2006-09-06 22:35 floral.png
-rw-r--r-- 1 root root 246 2006-09-06 22:35 flowers.png
-rw-r--r-- 1 root root 3,4K 2006-09-06 22:35 Foggy1.jpg
-rw-r--r-- 1 root root 15K 2006-09-06 22:35 fossil.png
-rw-r--r-- 1 root root 7,9K 2006-09-06 22:35 green_weave.png
-rw-r--r-- 1 root root 20K 2006-09-06 22:35 ice.png
-rw-r--r-- 1 root root 8,6K 2006-09-06 22:35 java.png
-rw-r--r-- 1 root root 81K 2006-09-06 22:35 kde_passion.jpg
-rw-r--r-- 1 root root 22K 2006-09-06 22:35 manila_paper.png
-rw-r--r-- 1 root root 7,9K 2006-09-06 22:35 Marble01.jpg
-rw-r--r-- 1 root root 11K 2006-09-06 22:35 marble.png
-rw-r--r-- 1 root root 274 2006-09-06 22:35 moss_ridge.png
-rw-r--r-- 1 root root 55K 2006-09-06 22:35 neurons.png
-rw-r--r-- 1 root root 30K 2006-09-06 22:35 No-Ones-Laughing-3.jpg
-rw-r--r-- 1 root root 8,8K 2006-09-06 22:35 numbers.png
-rw-r--r-- 1 root root 274 2006-09-06 22:35 ocean_stripes.png
-rw-r--r-- 1 root root 86K 2006-09-06 22:35 only_k.jpg
-rw-r--r-- 1 root root 1,7K 2006-09-06 22:35 Paper01.jpg
-rw-r--r-- 1 root root 4,8K 2006-09-06 22:35 paper.png
-rw-r--r-- 1 root root 15K 2008-03-10 11:36 pattern-boats.svg
-rw-r--r-- 1 root root 9,2K 2008-03-10 11:36 pattern-clouds.svg
-rw-r--r-- 1 root root 12K 2008-03-10 11:36 pattern-stars.svg
-rw-r--r-- 1 root root 241 2006-09-06 22:35 pavement.png
-rw-r--r-- 1 root root 25K 2006-09-06 22:35 Planning-And-Probing-1.jpg
-rw-r--r-- 1 root root 1,8K 2006-09-06 22:35 plasma.png
-rw-r--r-- 1 root root 12K 2006-09-06 22:35 purple_marble.png
-rw-r--r-- 1 root root 227 2006-09-06 22:35 qbist1.png
-rw-r--r-- 1 root root 4,9K 2006-09-06 22:35 qbist2.png
-rw-r--r-- 1 root root 245 2006-09-06 22:35 rattan.png
-rw-r--r-- 1 root root 441 2006-09-06 22:35 reset.png
-rw-r--r-- 1 root root 11K 2006-09-06 22:35 ridged_paper.png
-rw-r--r-- 1 root root 3,9K 2006-09-06 22:35 rough_paper.png
-rw-r--r-- 1 root root 1,8K 2006-09-06 22:35 sinus.png
-rw-r--r-- 1 root root 264 2006-09-06 22:35 sky_ridge.png
-rw-r--r-- 1 root root 274 2006-09-06 22:35 snow_ridge.png
-rw-r--r-- 1 root root 42K 2006-09-06 22:35 stonewall2.png
-rw-r--r-- 1 root root 32K 2006-09-06 22:35 terracotta.png
-rw-r--r-- 1 root root 32K 2006-09-06 22:35 Time-For-Lunch-2.jpg
-rw-r--r-- 1 root root 61K 2006-09-06 22:35 Totally-New-Product-1.jpg
-rw-r--r-- 1 root root 246 2006-09-06 22:35 triangles.png
-rw-r--r-- 1 root root 115K 2006-09-06 22:35 triplegears.jpg
-rw-r--r-- 1 root root 1,5K 2006-09-06 22:35 wavy_white.png
-rw-r--r-- 1 root root 40K 2006-09-06 22:35 Won-Ton-Soup-3.jpg
-rw-r--r-- 1 root root 17K 2006-09-06 22:35 wood.png

/usr/share/backgrounds/translucent:
total 40K
-rw-r--r-- 1 root root 23K 2008-03-10 11:36 ellipsis.svg
-rw-r--r-- 1 root root 15K 2008-03-10 11:36 tentacles.svg

/usr/share/backgrounds/waves:
total 2,1M
-rw-r--r-- 1 root root 423K 2008-09-03 15:03 bg-1280-1024.png
-rw-r--r-- 1 root root 535K 2008-09-03 15:03 bg-1600-1200.png
-rw-r--r-- 1 root root 599K 2008-09-03 15:04 bg-1920-1200.png
-rw-r--r-- 1 root root 152K 2008-09-03 15:01 bg-800-480.png
-rw-r--r-- 1 root root 161K 2008-09-03 15:01 bg-800-600.png
-rw-r--r-- 1 root root 158K 2008-09-03 15:18 bg.png
-rw-rw-rw- 1 root root 5,8K 2009-01-25 08:55 waves.xml
-rw-r--r-- 1 root root 5,7K 2008-09-03 15:10 waves.xml.asli
[root@msmunir1 backgrounds]#

Enjoy your picture!!!(MSMunir;Batan)
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