A glimpse of Linux before configuring TCP/IP in it.

Linux was developed by Linus Benedict Trovalds at the University of Helsinki in Finland in the year 1991.He  developed it as a hobby.But as  programmers  integrated the work of FSF(Free software foundation)with the Trovald's kernel, the base software for a complete Operating System emerged.Linux is multi-tasking,multi-user free operating system.Major linux distribution in these days are-Red Hat,Slackware,Caldera OpenLinux,Suse Linux,Debian/GNU,Corel,Ubuntu etc.

Linux File System:

/ -is called the root directory and is the gateway of all file system i.e. you can access other files once you enter the root system.

/bin- holds system programs used to operate the system.

/boot- holds all files needed boot the file system.kernel,boot loaders and the message files which defines the text printed on the screen during boot process.

/dev-All the devices files which are needed to access the devices like CD-ROM,HDD,Modem etc.

/etc-It contains configuration files used to control system intialization and configuration.

/home-It is the directory of the user.

/lib – Some of Linux OS commands use shared libraries,allowing executable files to be smaller.

/mnt – It is needed to mount external file system or devices.

/opt – It is storage for additional or add-on s/w.

Other than these files above there are also /root(not / but home directory of root user),/sbin,/tmp,/usr,/var directory.

Once you loaded any of the available versions of the OS, nowadays which is very easy, you need to find the commands available .Terminal is like command prompt windows OS and you can many more things with it unlike Windows. To open it press ctrl+alt+t. A small window will appear with probably black screen. Don’t frightened by that. Now with this you can do anything with this terminal.

It has a command called man which is used to see what any other command does. Suppose you want to know about what the cp command does, just type man cp, and it will give every information you need about cp.

Whatis  command is also same kind of command. If you want to anything about  nice linux commands just type-$whatis nice and press enter you’ll find entries in man pages of linux.

You can also use help and info option. For “help” just type –help after the command e.g man –help, this command will give you brief description of the man command. You can use info option by typing info and then the information you need e.g. $info time

There are many more commands and when you have a doubt about any command just use the above tools to know about them. Next I will discuss about some basic commands.

Some basic commands of Linux are ( the ‘$’ is not included in the command) -

·         $clear:  This command clears the screen you are working in and the screen is redrawn with new command line option on the top. Type man clear for more options

·         $whoami: This outputs your user name.

·         $passwd: You can use it change the passwd of current user. If you are root user you can change password of any user through this command.

·         $last: Use last to find out who has recently used the system, which terminal they used and when they logged out. last  followed by username gives particulars of above information for the user.

·         $ps: ps with no arguments list the processes you are running in your current shell session. The output will look like this-]

PID	TTY	STAT	TIME	COMMAND
193	1	S	0.01	-bash
204	1	S	0.00	ps

To list all process for a specific user type ps –u “username”

 ps aux – to know all the processes running on the system.

·         $top: to see continually updated display of the current system processes.

·         $echo: This command is used to write something on the shell. e.g. ego Isn\’t it a command? –will output Isn’t it a command? On the terminal. Mainly used to give some message to the user after some operation.

·         $kill:  this command is used to kill a job. Type job number as argument e.g kill %2- this will kill the job number 2.

·         $cp: To copy a file or folder. Use cp oldfile newfile to do it.

·         $mv: To move a file to a new location.

These are some basic commands of Linux to give you a basic idea.There are thousands of commands used and you can learn.Next we’ll learn about tcp/ip configuration with linux.