BASH/C3/Here-document-and-Here-string/English-timed

Time	Narration
00:01	Dear friends, welcome to the spoken tutorial on HERE document and strings.
00:08	In this tutorial, we will learn about
00:11	special-purpose redirection called Here documents and Here strings
00:17	with the help of some examples.
00:20	To follow this tutorial, you should have knowledge of Shell Scripting in BASH.
00:26	If not, for relevant tutorials, please visit our website which is as shown. http://www.spoken-tutorial.org
00:32	For this tutorial, I am using:
00:34	* Ubuntu Linux 12.04 Operating System
00:39	* GNU BASH version 4.2
00:42	Please note, GNU Bash version 4 or above is recommended for practice.
00:49	Let us learn about 'Here' document.
00:52	* It is a special purpose block of text or code.
00:56	* It is a form of I/O redirect.
01:00	* It feeds a command list to an interactive program or command line.
01:06	* It can be treated as a separate file.
01:10	* It can also be treated as multiple line input redirected to a shell script.
01:17	Syntax is-
01:18	command space less than less than space HERE.
01:24	After this, on the next line, we can give the text inputs.
01:29	It can consist of any number of lines.
01:33	Here, text1, text2, textN are the text inputs.
01:40	After the text inputs, on the next line, we type the keyword HERE again.
01:46	It denotes the closing of HERE document.
01:50	Let us understand this with an example.
01:53	I will open a file named here dot sh .
01:59	The first line of code is the shebang line.
02:04	Let me put a block of code after this line.
02:09	'wc' represents word count.
02:12	wc hyphen w counts the number of words in the HERE document.
02:20	The block of code or text until the second occurrence of HERE will be treated as a file.
02:28	The content present in HERE document is an input to the command wc hyphen w.
02:36	HERE acts as a delimiter for wc hyphen w command while reading multi-line input.
02:47	If we try to execute the same command in the terminal, we should get '4' as an output.
02:55	This is because we have passed four words to the command wc hyphen w.
03:03	Now click on Save to save the file.
03:06	Let us switch to the Terminal using Ctrl, Alt and T keys simultaneously on your keyboard.
03:15	Type: chmod space plus x space here dot sh
03:22	Press Enter.
03:24	Type: dot slash here dot sh
03:27	Press Enter.
03:30	We can see the output as 4
03:33	that is, number of words in 'Here' document is 4.
03:38	Come back to our program.
03:41	Let us add two more words here, at the beginning of the text.
03:47	Hello and welcome to Bash learning.
03:52	Click on Save.
03:54	Let us execute the program again.
03:57	On the terminal, type: dot slash here dot sh
04:04	Press Enter.
04:06	Now the output is 6 because we added two more words to our text.
04:13	We can also pass an argument to the Here document.
04:18	Let us see how to do this with an example.
04:22	Let me open a file named hereoutput dot sh.
04:28	The command cat will concatenate files and print the standard output.
04:35	Note that we have used the string "this" instead of "HERE".
04:41	It’s not necessary that you always have to use the delimiter HERE.
04:47	You can use any other delimiter also.
04:51	This line will display the 0th (zeroth) argument.
04:55	The 0th (zeroth) argument, by default, is the filename.
05:00	This line will display the 1st argument passed to the program.
05:05	And this line will display the 2nd argument passed to the program.
05:09	Here we have to close the document using the same delimiter this.
05:17	Save the file. Let us now execute the program.
05:21	On the terminal, type: chmod space plus x space hereoutput dot sh.
05:29	Press Enter
05:32	Type: dot slash hereoutput dot sh space Sunday space Monday
05:40	The output is displayed as:
05:43	"0'th argument is: dot salsh hereoutput dot sh" which is the filename.
05:49	"1st argument is: Sunday"
05:51	"2nd argument is: Monday" .
05:55	Let us learn about "Here" string now.
05:59	* Here string is used for input redirection from text or a variable.
06:06	* The input is mentioned in the same line within single quotes.
06:12	The syntax is- command space three 'less than symbols' space within single quotes write string
06:22	Let us understand this with an example.
06:25	I will open the same file here dot sh.
06:30	Here at the end, I will type: wc space hyphen w three less than symbols space within single quotes Welcome to Bash learning.
06:44	This will redirect the string within quotes to the command wc hyphen w.
06:52	Now click on Save to save the changes.
06:55	We will switch to the Terminal.
06:58	Now type: dot slash here dot sh.
07:03	We can see the output as 6 and 4.
07:08	Number of words in here document is 6 and number of words in here string is 4.
07:15	Likewise, you can write your own Here strings.
07:20	This brings us to the end of this tutorial.
07:23	Let us summarize.
07:25	In this tutorial, we learnt about:
07:27	* HERE document
07:29	* HERE string.
07:31	As an assignment, convert a string to uppercase using:
07:36	* Here document
07:37	* Here string.
07:39	Hint: tr space a hyphen z space capital A hyphen capital Z.
07:47	This is the command to convert characters from lower to upper case.
07:54	Watch the video available at the link shown below.
07:57	It summarizes the Spoken-Tutorial project.
08:01	If you do not have good bandwidth, you can download and watch it.
08:06	The Spoken Tutorial project team: Conducts workshops using spoken tutorials.
08:12	Gives certificates to those who pass an online test.
08:17	For more details, please write to contact@spoken-tutorial.org
08:25	Spoken Tutorial Project is a part of the Talk to a Teacher project.
08:29	It is supported by the National Mission on Education through ICT, MHRD, Government of India.
08:38	More information on this mission is available at the link shown below. http://spoken-tutorial.org\NMEICT-Intro
08:44	The script has been contributed by FOSSEE and Spoken-Tutorial teams.
08:50	This is Ashwini Patil from IIT Bombay, signing off.
08:54	Thank you for joining.

Contributors and Content Editors

Gaurav, PoojaMoolya, Pratik kamble, Sandhya.np14