Shell scripting for linux beginners. Get started with Linux

In this movie we will look at the very first look of linux. We will explore to open terminal and listening of directory contents. Further we will learn to create new directories and files. We will create file using vi editor and explore its content using cat command.

This statement is true because there are special files that are more than just files (named pipes and sockets, for instance), but to keep things simple, saying that everything is a file is an acceptable generalization. A Linux system, just like UNIX, makes no difference between a file and a directory, since a directory is just a file containing names of other files. Programs, services, texts, images, and so forth, are all files.

In this movie we will about the file management in detail. We will explore that linux only have files and directories in file management. We will learn to copy the files and well as to move the files. Further we will explore to delete files and problems in deleting directories. A brief tour to ifconfig is also given.

In this movie we will explore the concept of directory traversing. Giving the relative and absolute path in linux is a simple and easy concept. Further we will explore the meaning of dot and dot dot while doing an long listening of directories. We will also take a look on errors while creating the directories.

For a shell scripter, Linux permission is very important topic. In linux, unlike windows exe extension doesn't really matters. So one should understand the topic of permissions. This movie will talk in detail about the root, group and others as well as about the permissions like read, write and execute.

Every directory or file in the Linux file system contains settings for who can read, write or execute the file. These settings are called permissions. Each file or directory is assigned to a specific user and group.

We can connect 2 commands together using pipes. The output of one command can be fed as input to another command using pipes. We will also take a quick look at grep for searching a particular file. Further we will create our first script. Our script will be able to display time and date.

To create a process is very easy in linux. In this movie we will explore about the process in linux. There are some foreground process in linux and some background process in linux. We will learn to start foreground as well as background process in linux. Further we will explore the top command about the process in linux

Linux environment is a bit tricky. There are a few variables that you cannot use in linux because those variables are used as some default values for linux system. We will take a look at almost all of them and their meaning so that when we code, it keeps us away from unnecessary errors.

Vim is a text editor released by Bram Moolenaar in 1991 for the Amiga computer. The name "Vim" is an acronym for "Vi IMproved" because Vim was created as an extended version of the vi editor, with many additional features designed to be helpful in editing program source code.

In this movie we will learn what exactly is a shell. There are a variety of shells available for a linux user. There is a bourne shell, Korn shell and many more. We will also create our first sample script that just display date and current files in the directory. In our second shell, we will create a user interactive shell that asks what is your favourite colour.

Variables in shell scripting are bit tricky. Consider them as only of 2 types, 1. That you can use and 2. that you cannot use. There are also a few rules about creating variables like you can use alphabets, numbers and underscore but you cannot start with a number.

There are few predefined system variables that you cannot use for general purpose. For example $0 is used to get the file name and $1 for getting the first argument passed via command line. Learn more about all those pre defined varialbes in this movie.

Linux basic shell is not capable of doing basic operations like addition, subtraction and multiplication. Linux uses awk or expr to perform these operations. Further spaces and back quotes matters a lot in these operations. Small mistake can lead to failure of the operation

In shell scripting, we need to perform various check between 2 values. We have to check things like value a is greater than value a or might be chances that both values are equal. Shell scripting uses -lt for less than and -gt for greater than.

In the shell scripting, we can check for logical OR and logical AND. Also we can reverse the value i.e from TRUE, we can make it FALSE. Shell uses -o for OR operation and -a for AND operation. In this movie, we will take a close look on logical OR and logical AND.

A Linux administrator has to deal with lots of operations on files. He has to check if the file is present or not, what are the associated permissions on the file. Sometimes he needs to check if there is a file or directory. In this movie we will learn for the automation of these things.

Conditionals are very important part of programming. In this movie, we will explore about if and else structure in shell scripting. Important part about shell scripting is spaces. One wrong space can learn to failure of entire script. Also, if block is ended with fi in shell scripts

We can use nested if and else to check various condition but a smart choice would be to use switch and case. In shell scripting, switch and case is bit different in syntax. Case should always be close by esac. In this movie, we will explore the syntax further by an example.

Shell scripting supports many looping statements. While is one the mostly used loop syntax in shell scripting. In this movie we will take an example to understand while loop syntax by printing number from 0 to 10. This loop should be closed by done as the statements are written after do.

Shell scripting supports many looping statements. For is one the mostly used loop syntax in shell scripting. In this movie we will take an example to understand for loop syntax by printing number from 0 to 10.

All of the loops in shell scripting works till the condition is true and ends up if the condition is false. This until loop works just the opposite of other loops. It works till the logic is false and as soon as it get the true logic, it stops the flow of execution.

Looping has got some loop control keywords. In shell scripting, we have break and continue as loop control keywords. When we want to exit the loop for a one particular condition then we can use break keyword and break keyword will exit the loop. And if we want to skip just one flow of the loop for one particular condition, then we can use continue keyword.

Array is a important concept of shell scripting. If we want to declare 100 variables, the it would be rather good to declare array. Array get the contiguous memory allocation while the variables are scattered in the memory.

Executing a command from shell is bit tricky but mostly used. We have to use back quotes to execute the system command. We can store the output of that command in any variable and can modify it further. Also, we will explore escape sequence in this movie.

Few final words before ending the course. Linux is always a journey where you keep learning new things, even a 10 year experienced linux user will say the same words to you. Please visit linux forums to get more information and use the discussion. We will be adding more videos to this course in near future.