Linux-AWK/C2/Conditional-statements-in-awk/English-timed

Time	Narration
00:01	Hello and welcome to this spoken tutorial on conditional statements in awk.
00:07	In this tutorial, we will learn about- if, else, else if in awk.
00:15	We will do this through some examples.
00:19	To record this tutorial, I am using: Ubuntu Linux 16.04 Operating System and gedit text editor 3.20.1
00:32	You can use any text editor of your choice.
00:36	To practice this tutorial, you should have gone through the previous awk tutorials on our website.
00:43	You should have familiarity with any programming language like C or C++.
00:50	If not, then please go through the corresponding tutorials on our website.
00:56	The files used in this tutorial are available in the Code Files link on this tutorial page. Please download and extract them.
01:06	A conditional statement allows us to check a specified condition before performing an action.
01:14	Let’s learn how conditional statements like if, else, else-if work in awk.
01:22	Like any programming language, the syntax of 'if -else' statement is:
01:28	if conditional-expression1 is true then perform action1.
01:34	else if conditional-expression2 is true then perform action 2.
01:41	A number of else if statements may follow after this.
01:46	At the end, if none of the specified conditional expressions are true then perform action n.
01:54	The else and else-if portions are optional. Let us go through an example.
02:02	We will use the same awkdemo.txt file that we have used earlier.
02:10	Say, we need to give 50% increment in stipend to the students getting more than 8000 rupees.
02:19	Let us create an awk file for this condition.
02:23	Type the following code as shown, in a text editor and save it as cond dot awk. I have already done this.
02:34	The same file is also available in the Code Files link.
02:39	In this code, we have set the Output Field Separator as colon.
02:45	The first print statement prints the field headings.
02:50	Next, the 'if' statement will check whether the value of the 6th field is greater than 8000.
02:58	If yes, the second print statement will get executed.
03:03	$6 into 1.5 inside this print statement will multiply the 6th field value by 1.5 .
03:13	Let’s execute this code now.
03:16	Open the terminal by pressing CTRL, ALT and T keys.
03:22	Go to the folder in which you downloaded and extracted the Code Files using 'cd' command.
03:29	Now, type: awk space hyphen capital F pipe symbol within double quotes space hyphen small f space cond dot awk space awkdemo dot txt. Press Enter.
03:49	The output shows only one student’s record with the incremented stipend who fulfilled the condition.
03:57	Now, suppose the rule changes: 50% increment in stipend for students who get more than 8000 rupees.
04:07	Otherwise, give 30% increment. How can we do that?
04:13	We need to add an 'else' block.
04:16	Switch to the cond dot awk file once again.
04:21	Let us add the following line of code. Before the last closing curly brace press Enter.
04:30	else press Enter.
04:33	print space dollar 2 comma dollar 6 comma dollar 6 into 1.3
04:42	Save the file and switch to the terminal.
04:46	Press the up-arrow key to get the previously executed command and press Enter.
04:53	Observe the output now. Yojna Chaudhury was previously getting 1000. Now she is getting 1300.
05:04	Let’s change the rules again. 50% increment for student getting more than 8000 rupees.
05:13	40% increment for student getting more than 4000 rupees. Otherwise, give 30% increment.
05:23	Switch to the code. Update the code as shown.
05:29	Save the file and switch to the terminal.
05:33	Let me clear the terminal.
05:36	Now, press up-arrow key to get the previously executed command and press Enter.
05:44	This time, notice that the student Mira Nair has got 40% increment.
05:51	This brings us to the end of this tutorial.
05:54	Let us summarize. In this tutorial, we learnt about Conditional statements like: if , else, else if in awk.
06:05	As an assignment, give grades according to the rules: If mark is greater than equal to 90, grade will be A.
06:15	If mark is greater than equal to 80 but less than 90, grade will be B.
06:23	If mark is greater than equal to 70 but less than 80, grade will be C.
06:30	If mark is greater than equal to 60 but less than 70, grade will be D. Otherwise, grade will be F.
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07:08	Spoken Tutorial Project is funded by NMEICT, MHRD, Government of India. More information on this mission is available at this link.
07:20	The script has been contributed by Antara. And this is Praveen from IIT Bombay, signing off. Thanks for joining.

Contributors and Content Editors

PoojaMoolya, Sandhya.np14