Shell Scripting On Kali Linux

SHELL SCRIPTING

PART 1

INTRODUCTION

A shell is the interface between us and the kernel.And in this tutorial we are going to learn shell scripting .

First we start with the basic commands.And this tutorial is the basic tutorial , soon we will cover the advanced shell scripting .

And the operating system we use is ” Kali-Linux”.

Now go through with it and practise as much as you can .

SIMPLE COMMANDS

whoami

SYSTEM DATE AND CALENDER

To see the calender in linux we use the cal command .

As you enter the cal command , it will show you the current month calender.

See the below image for more details –

2013 CALENDER

Now if you are interested to view the 2013 calender , then enter the commands as shown below.

Command : cal 2013

See the below image for more details –

CREATING FILES AND DIRECTORIES

TOUCH COMMAND

Using touch command you can create the empty files in linux .

Also you can create more than 1 files together .

These are the empty files but you can also put text inside it using different text editors like vim , nano etc .

Example : See the below image i have created 3 empty files together using touch command .

CREATING DIRECTORIES

To create directory , we have to use the mkdir command .

Syntax : mkdir < directory name >

Example : See the below example for more details –

CHANGING DIRECTORY

To change directory you can simply use the ‘cd’ command .

See the below image for more details –

CREATING TEXT FILE USING CAT COMMAND

To create file use the command cat > filename

Then enter the text .

To terminate press ctrl+d.

See the below image for more details –

TO VIEW FILES

To view files you have to use ‘ < ‘ (less than ) sign as shown in the below example .

Example : cat < hackingDNA

Here hackingDNA is the filename .

See the below image for more details –

MERGE FILES

Merge files means joining two files together and put it into one single file .

Example : In the below example you can see two files :

hackingDNA

test

Then we put these two files into 1 single file i.e merge.

And at the last we view the merge file using ‘cat < merge’ command .

See the below image for more details –

RENAMING AND DELETE FILES AND DIRECTORIES

RENAME

To rename file mv command is used .

Syntax : mv filename newfilename

Example : mv test test1

See the below image for more details –

CREATING AND DELETING DIRECTORIES

COPY FILE INTO MUKUND DIRECTORY

LINK BETWEEN FILES : hardlink example

SOFTLINK EXAMPLE

In this example , i use ” ln -s ” to create a soft link .And also i link mukund to the mukund_soft .

When we use the ls command , you will observe the color of the soft link file , it’s different from others.

So now when i remove the mukund file and then try to access the mukund_soft file , you will observe you cannot see that file because you have deleted the hardlink (i.e mukund ).

FILE PERMISSION
CREATING A SAMPLE FILE

USING OF ” ls “

VIEW FILES AND DIRECTORY WITHOUT PERMISSION

LONG MODE ( ls -l )

DISPLAY ALL THE HIDDEN FILES (ls -a)

DISPLAY ALL WITH INODE (ls -i )

CHANGE FILE PERMISSION WITH CHMOD

Giving numeric permission is the easiest method .

Numeric permission : 4 is for Read , 2 is for write and 1 is for execute .

So for example : If you want to give rwx permission to group , users and other , you have to enter the numeric value 777 as shown in the below image .