Your own installed CIDR tables

When setting up networking, one of useful tool is the cidr tables, where you can refer the netmask and you can determine the cidr length for your netmask. Usually people will search the internet for network calculator or try to search for the cidr table. There is another easy way for you to have a cidr table installed in your computer and you can refer to it anytime you want using a single command. The package is perl-Net-IP. Install it using yum.

# yum install perl-Net-IP

After the installation finished, you can refer to the cidr table using the below command:

# iptab

There you go, a cidr table installed in your own computer for your own reference anytime. Have fun :-)

Sending message to users

To send message to a particular user, you have to know what is the user tty. You can do this by typing:

# w

This command is used to show who is logged on and what they are doing. The output of the above command is usually like below(Click to see the image clearly):



To send message to a specific user:

$ write username tty

Example, to send message to user user1:

$ write user1 pts/3

Write you messages, and then press Ctrl-d to exit 'write'

To send message to all connected user, use wall command:

$ wall

Type your message and Ctrl-d to exit 'wall'

Mounting LVM Disk using Ubuntu livecd

Mounting is an easy process to do, provided the filesystem type you are using is supported. What happen when you have an LVM formatted disk, and you need to mount it because the disk cannot be booted and a hell lot of valuable data kept inside?? Do not worry, because the solution is here.......

1. Get a live cd, for example, Ubuntu. For this article, I use Ubuntu 6.06 (I cannot find any latest version of ubuntu at my place)

2. Boot using the live cd. Search for these tools: lvm2. If the cd do not have it, install it.
# apt-get install lvm2

3. To make sure the harddisk is recognised, you can use fdisk
# fdisk -lu

4. Once installed, run pvscan to scan all disks for physical volume. this to make sure your LVM harddisk is detected by Ubuntu
# pvscan
PV /dev/sda2 VG VolGroup00 lvm2 [74.41 GB / 32.00 MB free]
Total: 1 [74.41 GB] / in use: 1 [74.41 GB] / in no VG: 0 [0 ]


5. After that run vgscan to scan disks for volume groups.
# vgscan
Reading all physical volumes. This may take a while...
Found volume group "VolGroup00" using metadata type lvm2


6. Activate all volume groups available.
# vgchange -a y
2 logical volume(s) in volume group "VolGroup00" now active

7. Run lvscan to scan all disks for logical volume. You can see partitions inside the hard disk now active.
# lvscan
ACTIVE '/dev/VolGroup00/LogVol00' [72.44 GB] inherit
ACTIVE '/dev/VolGroup00/LogVol01' [1.94 GB] inherit

8. Mount the partition to any directory you want, usually to /mnt
# mount /dev/VolGroup00/LogVol00 /mnt

9. You can access the partition in the /mnt directory and can backup your data

Combining multiple network interface into single interface (bond)

Bonding is a process of combining more multiple network interfaces as one interface. The main objective of bonding is to improve the performance of both network interface. Using this way, more load and data can be handled by the bonded network interface rather than using single network interface. In this how to, I will use only two interfaces as example.

1. Create bond configuration file (example bond0)
# vim /etc/sysconfig/network-scripts/ifcfg-bond0

2. Put below configuration inside the bond0 configuration file
DEVICE=bond0
IPADDR=192.168.1.20
NETWORK=192.168.1.0
NETMASK=255.255.255.0
USERCTL=no
BOOTPROTO=none
ONBOOT=yes

Replace above ip address, network and netmask with actual details and save the configuration file

3. Open the first network interface configuration file
# vim /etc/sysconfig/network-scripts/ifcfg-eth0

4. Append with the below details and save
DEVICE=eth0
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

5. Open the second network interface configuration file
# vim /etc/sysconfig/network-scripts/ifcfg-eth1

6. Edit the file to become like below and save
DEVICE=eth1
USERCTL=no
ONBOOT=yes
MASTER=bond0
SLAVE=yes
BOOTPROTO=none

7. Load bond module
# vim /etc/modprobe.conf

8. Append below details and save
alias bond0 bonding
options bond0 mode=balance-alb miimon=100

9. Load the bonding module
# modprobe bonding

10. Restart network
# /etc/init.d/network restart

11. You can check whether your bonding is ok by using ifconfig command
# ifconfig

The output should be something like below

bond0     Link encap:Ethernet  HWaddr 00:0C:29:C6:BE:59
inet addr:192.168.1.20  Bcast:192.168.1.255  Mask:255.255.255.0
inet6 addr: fe80::200:ff:fe00:0/64 Scope:Link
UP BROADCAST RUNNING MASTER MULTICAST  MTU:1500  Metric:1
RX packets:2804 errors:0 dropped:0 overruns:0 frame:0
TX packets:1879 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:0
RX bytes:250825 (244.9 KiB)  TX bytes:244683 (238.9 KiB)

eth0      Link encap:Ethernet  HWaddr 00:0C:29:C6:BE:59
inet addr:192.168.1.20  Bcast:192.168.1.255  Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fec6:be59/64 Scope:Link
UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
RX packets:2809 errors:0 dropped:0 overruns:0 frame:0
TX packets:1390 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:251161 (245.2 KiB)  TX bytes:180289 (176.0 KiB)
Interrupt:11 Base address:0x1400

eth1      Link encap:Ethernet  HWaddr 00:0C:29:C6:BE:59
inet addr:192.168.1.20  Bcast:192.168.1.255  Mask:255.255.255.0
inet6 addr: fe80::20c:29ff:fec6:be59/64 Scope:Link
UP BROADCAST RUNNING SLAVE MULTICAST  MTU:1500  Metric:1
RX packets:4 errors:0 dropped:0 overruns:0 frame:0
TX packets:502 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:258 (258.0 b)  TX bytes:66516 (64.9 KiB)
Interrupt:10 Base address:0x1480

Installing wireless on fedora 7 IBM Thinkpad r60 machine

You just bought a new laptop, IBM Thinkpad R60. Since you are an open source fans, you have decided to install the latest stable version of fedora, the fedora 7. After finish installing operating system, you try to access your office's wireless internet connection. but to your surprise there is no wireless options can you find on the start up menu. Don't panic, because there is a way how to configure your new laptop so that it can access wireless internet connection.

1. Check your wireless adapter.
$ cat /etc/sysconfig/hwconf | grep -i wireless
or
$ kudzu -p | grep -i wireless

2. The outcome usually will be like this: desc: "Intel Corporation 3945ABG Network Connection"
If your outcome of the command is also similar to the above, then you are in the right place :-).

3. The driver of that wireless device is not pre-installed on Fedora 7. So you have to install the driver from additional repository. Access you machine as root, and create file /etc/yum.repos.d/atrpms.repo
$ vim /etc/yum.repos.d/atrpms.repo
Insert the following content in the atrpms.repo
[atrpms]
name=Fedora Core $releasever - $basearch - ATrpms
baseurl=http://dl.atrpms.net/fc$releasever-$basearch/atrpms/stable
gpgkey=http://ATrpms.net/RPM-GPG-KEY.atrpms
gpgcheck=1

Import also the atrpms signing key
rpm --import http://ATrpms.net/RPM-GPG-KEY.atrpms

4. Install ipw3945 driver.
$ yum install ipw3945

5. You have to start the daemon in order for the driver to work. Add /sbin/ipw3945d to your /etc/rc.local
$ echo "/usr/sbin/ipw3945d" >> /etc/rc.local

6. Restart your machine.

7. You can also activate a service named NetworkManager to easily choose from GUI the wireless connection that you desire.
$ NetworkManager
$ chkconfig NetworkManager on - This command set NetworkManager to start on boot

8. You can scan for wireless network around you by using the below command
$ iwlist scan

Changing resolution and refresh rate in ubuntu

You boot up your ubuntu box as usual. Suddenly you notice something wrong: your resolution has changed without you changing it. You go to system preference and try to change the display resolution, but there is no optinon for your preferred setting. Don't panic, there still hope for your ubuntu machine besides reformat :-).
This is what you can do to repair back the display problem. You have to reconfigure Xorg. But before you do anything, please backup your configuration file just in case anything bad happens.

Backup your xorg.conf file
$ sudo cp /etc/X11/xorg.conf /etc/X11/xorg.conf.backup

This is how you can reconfigure Xorg

1. Stop your gdm (Gnome display manager), or kdm (KDE display manager) if you use kde desktop environment.
$ sudo /etc/init.d/gdm stop (or kdm for kde)
2. Reconfigure your xorg
$ dpkg-reconfigure xserver-xorg
3. Follow all the instruction. By default, choose 'yes' or 'ok' for every options
4. After finish reconfigure, start back gdm or kdm
$ sudo /etc/init.d/gdm start (or kdm for kde)

Hope this can help.

Postgresql quickstart

Reference on commands commonly used in postgresql administration. Enjoy....

1. To start postgres
# /etc/init.d/postgresql start
2. To stop postgres
# /etc/init.d/postgresql stop
3. To start using postgres, change to user postgres
$ su - postgres
4. To create new database
$ createdb dbname
5. To delete database
$ dropdb dbname
6. To access database
$ psql dbname
7. To dump database (backup)
$ pg_dump dbname > backup.out
8. Reload db from file
$ psql -d dbname -f db.out
9. To dump all database to file
$ pg_dumpall > dumpall.sql
10. Reload all from file
$ psql -f dumpall.sql
11. List database
$ psql -l
12. Clean all database
$ vacuumdb --quiet --all

Commands inside psql (PostgreSQL interactive terminal)

1. Access psql
# psql
2. Get help about commands
# \h
3. Quit psql
# \q
4. Import from file
# \i input.sql
5. Show databases
# \l
6. Show tables
# \dt
7. Show users
# \du
8. Connect to database
# \c dbname
9. Change user password
# \c template1
# ALTER USER postgres with password 'new_password';
10. Clean database
# VACUUM FULL;
11. Help on syntax command
# \h SYNTAXNAME

Turning on bind query logging

If you want to turn on the query logging for bind, you can use the rndc command.

$ rndc querylog

To see whether your querylog is on or off, use this below command:

$ rndc status
or
$ /etc/init.d/named status

After running the above command, you can see these lines:

[root@secondary-dns ~]# rndc status
number of zones: 5
debug level: 0
xfers running: 0
xfers deferred: 0
soa queries in progress: 0
query logging is ON
recursive clients: 0/1000
tcp clients: 0/100
server is up and running

Converting flv files to avi and mpeg

In linux we have a good tool, although text based, to convert between various video format. The tool is ffmpeg. This article will guide you on how you can convert flv format video to avi and mpg.

1. change your directory to the directory where your flv video is located.

2. run ffmpeg command:
$ ffmpeg -i input.flv output.avi
where -i stands for input and output.avi is the output file in avi or mpg.

3. For more advanced setting, you can use the command below
$ ffmpeg -i input.flv -ab 56 -ar 22050 -b 500 -s 320x240 output.mpg
where -ab is audio bitrate with default of 64kbps
-ar is audio samplerate with default of 44100Hz
-b is video bitrate with delault of 2000kbps
-s is size with default of 160x128px

Resetting mysql root password

Sometimes you have to access a mysql database and you somehow does not know the password or the user of the database. The last resort is you have to use the root password but the password is unknown. There is always the way to solve anything and the way to reset the root password is described below. Enjoy!

1. Open a terminal and stop mysqld daemon if it has been started: $ /etc/init.d/mysqld stop
2. Type this command: $ mysqld_safe --skip-grant-tables
3. Open a new terminal, and access mysql database using root:
$ mysql -u root mysql
4. Change root password to new password: mysql> update user set password=password('newpassword') where user='root';
5. flush mysql privileges: mysql> flush privileges;
6. Exit mysql: mysql> exit
7. Close the terminal with the mysqld_safe command
8. Restart mysql: $ /etc/init.d/mysqld start

Setting up your own ntp server

NTP or network time protocol is a protocol that will synchronize the time of a computer client or server to another server or reference time source, such as a radio or satellite receiver or modem. Typical NTP configurations utilize multiple redundant servers and diverse network paths in order to achieve high accuracy and reliability.
Follow the below setup to install your ntp server:

1. install ntp: $ yum install -y ntp

2. edit ntp.conf: $ vi /etc/ntp.conf
example of ntp.conf:
# Permit time synchronization with our time source, but do not
# permit the source to query or modify the service on this system.
restrict default kod nomodify notrap nopeer noquery
restrict -6 default kod nomodify notrap nopeer noquery

# Permit all access over the loopback interface. This could
# be tightened as well, but to do so would effect some of
# the administrative functions.
restrict 127.0.0.1
restrict -6 ::1

# Hosts on local network are less restricted.
#restrict 192.168.1.0 mask 255.255.255.0 nomodify notrap

# Use public servers from the pool.ntp.org project.
# Please consider joining the pool (http://www.pool.ntp.org/join.html).
#server 0.rhel.pool.ntp.org
#server 1.rhel.pool.ntp.org
#server 2.rhel.pool.ntp.org
#server mst.sirim.my prefer
#server my.pool.ntp.org

#broadcast 192.168.1.255 key 42 # broadcast server
#broadcastclient # broadcast client
#broadcast 224.0.1.1 key 42 # multicast server
#multicastclient 224.0.1.1 # multicast client
#manycastserver 239.255.254.254 # manycast server
#manycastclient 239.255.254.254 key 42 # manycast client

# Undisciplined Local Clock. This is a fake driver intended for backup
# and when no outside source of synchronized time is available.
#server mst.sirim.my prefer
#server my.pool.ntp.org

# Drift file. Put this in a directory which the daemon can write to.
# No symbolic links allowed, either, since the daemon updates the file
# by creating a temporary in the same directory and then rename()'ing
# it to the file.
driftfile /var/lib/ntp/drift

# Key file containing the keys and key identifiers used when operating
# with symmetric key cryptography.
keys /etc/ntp/keys

# Specify the key identifiers which are trusted.
#trustedkey 4 8 42

# Specify the key identifier to use with the ntpdc utility.
#requestkey 8

# Specify the key identifier to use with the ntpq utility.
#controlkey 8

3. If the server you are setting up do not have internet connection, you can synchronize it with the local time of the server itself. Just comment the server part, and change it to 127.127.1.0. The sratum level is for determining what level this time server is set up for. Stratum 0 usually refers to real clock, for example atomic (cesium, rubidium) clocks or GPS clocks or other radio clocks. Stratum 1 is the machine connected to stratum 0 devices.

#server mst.sirim.my prefer
#server my.pool.ntp.org
server 127.127.1.0
fudge 127.127.1.0 stratum 10

4. synchronize the server's time with the ntp server: $ ntpdate -du mst.sirim.my

5. start ntp service: $ /etc/init.d/ntpd start

In the client machine, just type: $ ntpdate -du ntpservername. You can also put this command in crontab for the client to be update frequently

Installing lighttpd in Centos 5 for x86_64

Lighttpd is a fast and optimized web server that prioritize performance. To install this web server application, some additional work need to be done because there is no rpm compiled version of this web server for x86_64 architecture yet. So we have to do the hard work by getting the spec file, compiling the source and all. Steps to be taken to successfully install lighttpd on Centos 5 x86_64 machine are as below:

1. get the rpm source file for lighttpd from here
2. install the requirement needed to compile the source: pcre-devel 6.6-1.1, mysql-devel 5.0.22-2.1 and lua-devel. The first two can be be installed from yum: $ yum install -y pcre-devel mysql-devel. The last one can be downloaded from here and its dependencies can downloaded from here. Install the last dependencies using: $ rpm -Uvh lua-5.1.2-1.el5.kb.x86_64.rpm lua-devel-5.1.2-1.el5.kb.x86_64.rpm
3. Install the lighttpd rpm source file: $ rpm -Uvh lighttpd-1.4.16-1.el5.src.rpm
4. The spec file for lighttpd will be saved into /usr/src/redhat/SPECS
5. Compile the spec file: $ rpmbuild -bb /usr/src/redhat/SPECS/lighttpd.spec
6. The rpm for lighttpd will be saved into /usr/src/redhat/RPMS/x86_64. Install lighttpd: $ rpm -Uvh /usr/src/redhat/RPMS/x86_64/lighttpd-1.4.16-1.x86_64.rpm
7. Check whether your lighttpd has been installed: $ rpm -qa | grep lighttpd If the result is as picture, your lighttpd is installed

Using crontab scheduler

Crontab is a tool for scheduling tasks for the computer to run. It will automate the jobs that needs to be done but will be difficult to be done by human because of time limitation. There are only 4 options for crontab which are -u, -e, -l and -r and the usage is described below:

• crontab -l - list all the crontab on standard output
• crontab -e - edit the current crontab using the editor specified by the VISUAL or EDITOR environment variables
• crontab -r - remove the current crontab
  
• crontab -u - specify the user
• example: $ crontab -u username -l - this command will list the crontab belongs to the username

Crontab is set by running the crontab -e command and add the necessary time and the command to be run on that particular time. Crontab scheduling format are as below:

* * * * * command to be run

1st * is for minutes (0-59)
2nd * is for hour (0-23)
3rd * is for day of month (1-31)
4th * is for month of year (1-12)
5th * is for day of the week (0-7) where 0=Sunday and 7=Sunday

Example:
To backup your pc using rsnapshot everyday at 7.30 a.m.;

1. $ crontab -e
2. 30 7 * * * /usr/local/bin/rsnapshot daily
3. save your crontab setting

System backup using rsnapshot

Rsnapshot is a filesystem snapshot utility that we can use for free to backup our system. To use this tool, user must have perl, ssh and rsync installed in their machine. Rsnapshot is an ideal tool for backup because it saves a lot of hard disk space. This can be done because the space needed is roughly the size of one full backup plus a copy of each additional file that is changed. The installation is also simple as shown below:

1. install rsnapshot
   
• -> yum install rcsnapshot
2. after installation, do some setting in /etc/rsnapshot.conf . Some of the important settings are as below:
   
• snapshot_root - change it to your preferred directory
• cmd_cp - for linux user, uncomment this option
• backup script
• backup user@servername:/folder/to/backed-up destination/in/snapshot_root
  
• interval - set this to set the frequency of snapshot to be taken. Please note that it must be arranged from smaller unit(hourly) on top to bigger one. For example:
  
• interval daily 7 - this means snapshot will be taken 7 times a week
• interval weekly 4 - this means snapshot will be taken 4 times a month
3. Test the validation of the config file
   
• -> rsnapshot configtest
4. Test run your command
• -> rsnapshot -t daily
5. To backup, just run the below command(for daily)
   
• -> rsnapshot daily
  

Setting system clock and date

To set system clock and date using command, date command can be used.
This is how to do it:

-> date mmddttttyyyy.ss where;
mm - month
dd - day
tttt - time in hours and minutes
yyyy - year
ss - seconds

For example, to set the current date to 17 July 2007, 11:15 a.m., this command below can be used:

-> date 071711152007

To see the current date, the date command without argument can be used.

-> date

Setting default editor in ubuntu

To change the default editor for your ubuntu machine, here is the step:

1. type:
• $ update-alternatives --config editor
2. Select which editor that you want to set as default by typing its number. For below example, vim(1) is chosen.

Another method to do the similar task is by using command select-editor:

1. type the command
$ select-editor
Select an editor. To change later, run 'select-editor'.
1. /usr/bin/vim.tiny
2. /bin/ed
3. /bin/nano <---- easiest

Choose 1-3 [3]:

2. Choose from the list given. In the case above, if you want vim to be your default editor, type '1' and press 'enter'

3. Finish

SSH without password

Using the below steps, you can ssh to the server from client without the entering any password.
The machine which run the ssh command is the client
The machine that the client access using ssh is the server

1. Run the following command on the client
• -> ssh-keygen -t dsa
  
2. File id_dsa and id_dsa.pub will be created inside $HOME/.ssh
3. Copy id_dsa.pub to the server's .ssh directory
• -> scp $HOME/.ssh/id_dsa.pub user@server:/home/user/.ssh
4. Change to /root/.ssh and create file authorized_keys containing id_dsa content
• -> cd /home/user/.ssh
• -> cat id_dsa >> authorized_keys
5. Change "StrictModes yes" in /etc/ssh/sshd_config to "StrictModes no"
6. Restart ssh server
   
7. You can try ssh to the server from the client and no password will be needed
   
• -> ssh user@server

Another alternative to the above steps is to use ssh-copy-id command. The steps are:

1. Run the following command on the client
• -> ssh-keygen -t dsa
2. File id_dsa and id_dsa.pub will be created inside $HOME/.ssh
3. Copy the id_dsa.pub to the server's .ssh directory
• -> ssh-copy-id -i ~/.ssh/id_dsa.pub user@server
4. Change "StrictModes yes" in /etc/ssh/sshd_config to "StrictModes no"
5. Restart ssh server
   
6. You can try ssh to the server from the client and no password will be needed
   
• -> ssh user@server

Thanks to nailer for this information

Understanding Linux Runlevels

Unlike most non-unix operating system, Linux have many runlevels. They are numbered from 0-6 like below.

0 - halt
1 - Single user mode
2 - Multiuser, without NFS (The same as 3, if you do not have networking)
3 - Full multiuser mode
4 - unused
5 - X11
6 - reboot

This list is taken from /etc/inittab file where init will find its configuration setting. The default runlevel usually is set to runlevel 5 where it is the graphical mode of linux. Halt means shutdown and runlevels 1-3 are non graphical mode. You can switch your runlevel by using;

-> init

To check your current runlevel, you can use;

-> runlevel

To view this list;

-> vi /etc/inittab

Amarok cannot play mp3

If after you have installed media player amarok, and the player cannot play mp3 files, you have to install one more library: libxine-extracodecs

Run
-> sudo apt-get install libxine-extracodecs

or
use synaptic package manager to install the library

To search for string in files

To search for a string in all files from the given directory, grep command can be used. Type:
-> grep -R "string" /path

For example, to search for string "default" in /tmp directory, use this command:
-> grep -R "default" /tmp

Changing default editor for your linux machine

Below are the steps to be taken to change your default editor. Usually for Ubuntu, the default editor is pico and for Centos is vi.

1. To change your default editor to vi, type:
• -> export VISUAL=/usr/bin/vi
2. To make it permanent for current user, add the above line to /home/user/.bash_profile
3. To make it permanent globally, add the above line to /etc/profile
   

How to format your flash drive

This is how you can format your flash drive(thumbdrive, pendrive) in any linux machine

1. To see what is the filesystem for your flashdrive

• type -> df

2. Type -> mkfs /dev/sdb1
(The /dev/sdb1 is according to your outcome of the df command previously: refer above diagram)
This command will format the flash drive to ext3 format which is the default.
To format it to fat;
type -> mkfs -t vfat /dev/sdb1

Installing flash player to mozilla firefox on x86 64 bit machine

1. Download nspluginwrapper here
   
2. Once dowloaded, extract it.
3. Open the folder extracted and the folder inside it, double-click on "GetFlash". Select "Run in Terminal".
4. When finished, restart firefox.
   

rpm building error

When you try to build rpm file from source, if this error comes out:

error: Legacy syntax is unsupported: copyright
error: line 10: Unknown tag: Copyright: distributable

This error can be settled by modifying the spec file. Usually the source will have the spec file.

-> vi filename.spec

Then; change this line "Copyright: GPL" to "License: GPL". Save the changes.

Run back rpmbuild.

How to view the content of iso image

Sometimes we have an iso image in our computer. One of the way to view it is to burn it on a cd and then we can view it. The other method is we can use mount command.
Type this command on terminal:

-> mount -o loop filename.iso /path/to/directory

where;
/path/to/directory - directory where you want to deploy the iso

filename.iso - name of the iso file

Bug Buddy dialog box keeps opening on Ubuntu

I don't know what is the cause..... but sometimes this phenomenon happens. When the bug buddy keeps bugging you with this error message " The information about the crash has been successfully collected.
The application that crashed is not known to bug-buddy, therefore the bug report can not be sent to the GNOME Bugzilla. Please save the bug to a text file and report it to the appropriate bug tracker for this application.", the solution is,

1. Open your terminal. If cannot, press ctrl+alt+F1.
2. Type this command -> rm ~/.recently-used.xbel
3. Restart your pc.
   

Mounting cdrom

If you are using a pc with linux that does not have automount feature, here are the steps that you can do to mount it on linux terminal.

• After inserting the cd, create a folder. Usually we create a folder inside folder /mnt. Type --> mkdir /mnt/cdrom.
• To mount it, type --> mount /dev/cdrom /mnt/cdrom. This step will mount the content of the cdrom to the folder /mnt/cdrom
• After you finish, just type --> umount /mnt/cdrom to unmount it from the folder.

You can also use this steps for other devices such as flash drive. To check where is the folder containing the device, type --> df.
This command is for the user to see disk space usage.

List your hardware

If you want to view the hardware spec of your pc, you can use this command
--> lshw
This is how you see the hardware spec on your pc.



By default, this command is installed on ubuntu linux but not installed on Centos. You can use you tools like yum to install it
--> yum install lshw

Creating translation for dotproject

Dotproject is an open source project management system. It is built by default based in English language but whomever wants to translate it to their own native language, dotproject provide language management where the user can use other language in their dotproject. There are two ways to do this translation. First, if available, you can download the pre-translated configuration files from the internet and embed it in your dotproject system. Second, if there is no translation for your language available, you can create your own translation files and do the translation yourself. In this guide, I would like to show you how to do the translation yourself.
The steps:

1. Create a new directory under dotproject/locales directory and name it according to your language iso code. Give appropriate permission to this folder (ex: write permission for others). The code can be found at http://ftp.ics.uci.edu/pub/ietf/http/related/iso639.txtCreate locales.php inside yor newly created folder. This is the content of the file(put it inside php tags):

$dir = basename(dirname(__FILE__));
$LANGUAGE['aa_BB'] = array($dir, 'Language Name (in English)', 'Language name (in Language)', 'xxx');

• aa_BB is the iso 2 character language code 'aa', followed by the ISO 2 character country code 'BB' (http://www.bcpl.net/~j1m5path/isocodes.html)

• The first instance of the language name should be in English The second should be in the native language. The last field 'xxx' is the Microsoft language code (http://msdn2.microsoft.com/en-us/library/ms533052.aspx)

Example of locales.php file for Bahasa Melayu(put it inside php tags):

$dir = basename(dirname(__FILE__));
$LANGUAGES['ms_MY'] = array($dir, 'Malay', 'Bahasa Melayu', 'msl');

2. Create file lang.php inside the newly created folder. The content of the file is similar to the locales.php

3. Log in as system admin to your dotproject system. Go to System Admin > Translation Management and choose your language from the drop down menu. Start translating. DO NOT attempt to edit the INC files directly to create your translation - it won't work.

How to install yum on SuSE Linux 10.2

People using suse are familiar with yast. But in this article, I want to show how you can install yum, on your suse machine.

1. Download yum and all its dependencies from this link:
http://download.opensuse.org/distribution/10.2/repo/oss/suse/i586/

python-urlgrabber
python-sqlite
rpm-python
yum-metadata-parser (used option --nodeps)
yum

2. Install them all using this command: -> rpm -Uvh (name of packages above)
but for yum-metadata-parser use -> rpm -Uvh --nodeps yum-metadata-parser

3. Prepare yum config file
a. -> cd /etc/yum.repos.d/
b. create file with .repo (ex: suse.repo) containing:
[base]
name=OpenSUSE_10.2 Base
type=rpm-md
baseurl=http://download.opensuse.org/distribution/10.2/repo/oss/suse/
gpgcheck=1
gpgkey=http://download.opensuse.org/distribution/10.2/repo
/oss/gpg-pubkey-a1912208-446a0899.asc
enabled=1

4. yum is ready for usage.

how to check your kernel version

Sometimes you want to know the particulars about the kernel of your linux. This can be done using uname command.
To check kernel version:
->uname -v
To check kernel release:
->uname -r
To check kernel name:
->uname -s

Installing Package In ubuntu using dpkg

If you are using Redhat Linux, you are most probably using rpm or yum as your package manager. in ubuntu, you can use synaptic package manager as your package manager and thankfully it got GUI. But for those who like to learn command based package management in ubuntu, you can use apt or dpkg command.

If you already have any package with .deb extension in your computer, you can use dpkg to install it. First you have to change directory to the directory where the package is stored. Then run: -> dpkg -i namefile.deb
Remember you need to be superuser to do this.



Example on how to install flashplayer using dpkg from /home/oscc/Desktop/tools folder
(click on the picture to see image clearly)

To get more information about dpkg, type:
-> man dpkg

Checking installed package

To check installed packages on you redhat machine, this command can be used:
-> rpm -qa
Using this command, all packages installed will be printed to the screen. To filter the view to print only the package that you desire, use this command:
-> rpm -qa | grep packagename
example: -> rpm -qa | grep -i bind
This command can also be used: -> rpm -qa bind*

Viewing system's running processes

To view running processes, you can use ps command to list out the running processes.
To see every process on the system:
ps -e
ps -ef
ps -eF
ps -ely
To find the process that you want to see:
-> ps -e | grep nameoftheprocess

example: -> ps -e | grep httpd
The above command will print only the httpd process.

Yet another rpm building method

There is also another method of converting tarball to rpm instead of using rpmbuild -bb filename.spec. Using the method mentioned before requires the user to extract the tarball file first before we can use it. If we do not want to extract it first, we can use :

1. type ->rpmbuild -tb filename.tar.bz2
2. after the rpm file has been created; use ->rpm -Uvh filename.rpm to install it

That's all.

Knowing your linux release

Knowing what operating system and what is the release number are the basic of using any operating system. This information is usually stored in the /etc/ folder in linux. To view it you can type:

For Ubuntu:
cat /etc/lsb-release

For Redhat:
cat /etc/redhat-release

For SuSE:
cat /etc/SuSE-release

This line will be displayed(for Ubuntu):

DISTRIB_ID=Ubuntu
DISTRIB_RELEASE=6.10
DISTRIB_CODENAME=edgy
DISTRIB_DESCRIPTION="Ubuntu 6.10"

If you are not sure which file points to this info, you can go to the /etc file, and type:
ls *release
then:
cat lsb-release

Building rpm from source file

This is for the Redhat, SuSE and CentOS user out there. Sometimes when you try to search for rpm packages, the only thing that you find is the source file. You create rpm file using this source file:
1. save the source file(usually in tar.gz or tar.bz2 format)
2. extract the files-> tar -xvzf filename.tar.gz or tar -xvjf filename.tar.bz2
3. open the folder of the extracted file and find .spec file
4. type-> rpmbuild -bb filename.spec
5. see the error and continue according to the error until you finish creating rpm files
6. type-> rpm -Uvh filename.rpm to install

Hope this one can help.