Windows XP/Vista/7
Run ipconfig/all from a Command Prompt window.

• click Start, then Run, then type cmd in the text box.

• Type in ipconfig/all in the Command Prompt Windows and press enter

You should get something like this

Your MAC Address is listed under ‘Physical Address’ as a series of 6 groups of two digits, letters and numbers, separated by dashes, such as in the image below. Make sure you get the physical address of the correct network adapter – usually there are several listed.

Linux

On Linux systems, you must login as root user first before you find the Mac Address

• Launch your terminal
• Type the following command to become root user

[ahkwai@techkaki ~]$ su -
Password:

• Then, type ifconfig. Example:-


MAC OS X

Choose “System Preferences...” from the Apple menu. Then select “Network.” Double-click on “Airport” or “Built-in Ethernet” depending on how you access the Internet or your network.

For ‘Built-in Ethernet’, select the Ethernet tab.  Read the MAC address labeled ‘Ethernet ID:’.

I just downloaded .rar file. But i can’t open it under my Fedora operating systems. How to open it?

RAR is a proprietary compression format widely used today. By default, Fedora unable to open RAR files. So, you need to install a software called unrar.

How to install unrar on Fedora?

Just use yum command as follows :

# yum install unrar

Under Ubuntu, you need to type apt-get as follows to install unrar program:

# apt-get install unrar

How to use unrar?

Extract a RAR file into the current directory.

# unrar e [filename].rar

eg: # unrar e testing.rar

List contents of a RAR file

# unrar l [filename].rar

eg: # unrar l techkaki.rar

If you want to know more on how to use unrar function, you just type man unrar on your terminal.

Once you installed MySQL, you might need to set the MySQL root password to protect your DB. Actually how to do that?

Just type the following command on your terminal

[root@techkaki] # mysqladmin -u root password NEWPASSWORD

However, if you want to change (or update) a root password, then you need to use following command

 [root@techkaki] # mysqladmin -u root -p 'oldpassword' password newpass

Eg:

[root@techkaki] # mysqladmin -u root -p 'abcdef' password '123456'

There is a bug with the Gnome Network Manger on Ubuntu 8.10. We have to set the static ip address manually. Once the system is reboot, it will reverting back to DHCP setup.

This problem can be solve by remove the Gnome Network Manager. To remove the Gnome Network Manager, use the following command in the terminal:

sudo update-rc.d NetworkManager remove

After that, reboot your system.

Step 1 – How to set the static ip

We need to manually configure the network interface file when you want your Ubuntu run on static IP environment

Enter the following command into the terminal:

nano /etc/network/interfaces

After that, enter the following information to the network configuration files

auto lo eth0
iface lo inet loopback
iface eth0 inet static
address xxx.xxx.xxx.xxx(enter your ip here)
netmask xxx.xxx.xxx.xxx
gateway xxx.xxx.xxx.xxx(enter gateway ip here)

Please save it before you exit the configuration file.

Step 2 – Manually configure your dns configuration file:

Enter the following command into the terminal:

sudo nano /etc/resolv.conf

Once the DNS configuration open, enter the following information

# Generated by NetworkManager
nameserver xxx.xxx.xxx.xxx(enter your dns server ip)
nameserver xxx.xxx.xxx.xxx(enter your alt dns server ip)

Please save before you exit the configuration file.

Step 3 – Restart the network interfaces

Enter the following command in the terminal:

sudo /etc/init.d/networking restart

After that, your network interface should be able to run on new setting(static ip) even you restart your machine. You can try to check on by using ifconfig command in your terminal.

Just try it

By default, Mac OS X hide all the Hidden Files. For those familiar with Unix files and folders, you have probably noticed that folder like /usr, /bin, /etc do not show up in finder. Besides, files that start with a dot like .bash_history also out of your sight.

Is it possible to make those hidden files work in Finder? The answer is Yes. We can easily show the hidden files by using simple terminal command.

To show all the hidden files:-

• Launch Terminal
• Type “defaults write com.apple.finder AppleShowAllFiles TRUE” (without the quote)
• Type “killall Finder”(without the quote) to restart the Finder

After that, you will realize that all the hidden files are show on your Finder.

To hire the Hidden Files:-

• Launch Terminal
• Type “defaults write com.apple.finder AppleShowAllFiles FALSE”(without the quote)
• Type “killall Finder”(without the quote) to restart the Finder

Done!

You can add a group and add user to a group using unix command.

In this example, i use linux ubuntu to do it

Add a Group

sudo groupadd samba

Add user to Group

sudo adduser johnson samba

To check what Group user belong to

group [username]

eg:

root@ubuntu:/# groups test
test users

Add a existing user to existing group

usermod -g [group name] [username]

eg:

root@ubuntu:/# usermod -g it techkaki

date
Date displays the date and time of the system, used by root it can also be used to change the date and time of the system.

If you just enter:

date

You will get the date of the system, like this;

Fri May 18 19:36:53 MYT 2009

You can set the date by using root user:

Usage:

date nnddhhmm[[cc]yy][.ss]

Note:

• nn = month of the year (01 to 12)
• dd = day of the month (01 to 31)
• hh = hour of the day (00 to 23)
• mm = minute of the hour (00 to 59>
• cc = The first to digits of the year
• yy = The last two digits of the year
• .ss = The seconds

Example:

date –set 06:00 ;sets the time to 6:00AM

OR

hwclock

hwclock is a tool for accessing the Hardware Clock. You can display the current time, set the Hardware Clock to a specified time, set the Hardware Clock to the System Time, and set the System Time from the Hardware Clock.

SYNOPSIS

hwclock -r or hwclock –show
hwclock -w or hwclock –systohc
hwclock -s or hwclock –hctosys
hwclock -a or hwclock –adjust
hwclock -v or hwclock –version
hwclock –set –date=newdate
hwclock –getepoch
hwclock –setepoch –epoch=year

Example of change date and time.

hwclock –set –date=’08/18/07 21:08:40′ –localtime

I just learn to setup AMP on centos. Below are the steps

• Download a copy of CentOS Linux and install it
• Once your CentOS is installed. type yum install httpd to install apache web server
• type yum install php to install PHP
• Once PHP installed successfully, type yum install mysql-server mysql
• Once everything finish, type service httpd start to start your apache web server, screen will show you if web server service successfully started
• type service mysqld start to start your mysql server
• Once both services is running, you can point your browser to http://localhost and you should see a welcome page from CentOS
• To test php is running properly, go to /var/www/html and create an index.php file with the content below

In Unix, how do I quickly changing users on Linux without having to logout while you are using bash or any other command line interface.

The su command

Using the su command we can quickly change users in a bash terminal for that type the following command;

su – username

To login as a root user

su -s

To remove a directory that is full with other files and/or other directories, use the below command.

$ rm -rf directory

rmdir command can use to remove the empty DIRECTORY(ies)

$ rmdir directory