BOSS-Linux/C3/More-on-sed-command/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on More on sed.
00:06	In this tutorial, we will learn some More on sed commands, through some examples.
00:13	To record this tutorial, I am using
00:15	*Linux Operating System and
00:20	*GNU BASH version 4.2.24
00:23	Please note, GNU Bash version 4 or above is recommended to practice this tutorial.
00:30	As prerequisites,
00:33	You should know basics of Linux terminal.
00:36	You should be aware of sed tool.
00:39	For relevant tutorials please visit our website which as shown: http://spoken-tutorial.org
00:45	The major use of sed is substitution.
00:49	Replacing some pattern in the input with something else.
00:54	Let's first look at the original file seddemo.txt
01:00	Notice the word Kumar occurs two times in the fourth line and once in the sixth line.
01:10	If you want to replace all occurrences of ‘Kumar’ with ‘Roy’
01:15	Type on the terminal
01:17	sed space within single quote 's front slash / opening square bracket small k capital K closing square bracket umar slash Roy slash' after the single quotes space seddemo.txt
01:39	Press Enter.
01:42	Notice the fourth line.
01:45	Only the first occurrence of Kumar is changed to Roy, not the second one.
01:51	Sixth line had one occurrence of the word Kumar and this is replaced now.
01:57	So, we see only the first entry of the lines has been changed.
02:02	This is because, by default, the first matched entry of any line is substituted.
02:10	To substitute all the matched entries we need to use the flag g option.
02:17	Let me clear the prompt.
02:20	Type: sed space within single quotes 's front slash opening square bracket small k capital K closing square bracket umar slash Roy slash g' after the single quote space seddemo.txt Press Enter
02:43	Now, both entries of the fourth line are replaced.
02:47	We can make multiple substitutions in one go as well.
02:52	Say we want to replace the words electronics with the word electrical
02:57	And civil with metallurgy in the file seddemo.txt
03:04	Let me clear the prompt
03:06	Type: sed space hyphen e space within single quotes 's' front slash electronics slash electrical slash g’ after the single quote space hyphen e space within single quotes ‘s front slash civil slash metallurgy slash g’ after the single quotes space seddemo.txt
03:35	And press Enter.
03:38	You can see that the words are replaced.
03:41	Now we want to change the stream of Anirban from computers to mathematics.
03:49	In such case we would need to type:
03:52	sed space within single quotes 'front slash Anirban slash s slash computers slash mathematics slash g' after the single quotes space seddemo.txt
04:11	Press Enter.
04:13	We see that the stream is changed.
04:17	Let us understand what this is.
04:20	First we write sed then in single quotes we write the pattern to be matched.
04:27	This is Anirban.
04:29	Now after the slash comes the operation.
04:33	This is s that stands for substitution, as we have already seen.
04:40	Then we mention the pattern to be replaced which is computers.
04:46	Then the new word that would be substituted, which is mathematics.
04:52	We can also use sed to add or delete lines in the file.
04:59	Say we want to select those lines which do not have stream as electronics.
05:05	For that, we have the d flag.
05:09	Type: sed space within single quotes front slash electronics slash d after the single quotes space seddemo.txt space greater than sign space nonelectronics.txt
05:30	Press Enter.
05:32	To see the contents, type: cat space nonelectronics.txt
05:41	Say, at the start of the file we want to add a line Student Information.
05:49	For that we have the i action.
05:53	We need to type: sed space in single quotes '1i space Student Information' after the quote seddemo.txt
06:09	And press Enter.
06:12	You can see the output.
06:14	In fact, we can enter multiple lines like this.
06:19	Say, we want to add the two lines we would do it in a similar way.
06:25	Along with Student Information we also want to add academics in the next year.
06:33	So in that case we would write sed space in single quotes 1i space Student Information slash n 2013' after the quotes seddemo.txt
06:54	Press Enter
06:56	Notice slash n between the string ‘Information’ and ‘2013’.
07:04	slash n prints 2013 in the next line after ‘Student Information’
07:10	This brings me to the end of this tutorial.
07:14	Let us summarize,
07:16	In this tutorial we learnt,
07:18	Substitution
07:19	Replacement
07:20	And Insertion
07:23	As an assignment, Use the same text file seddemo.txt
07:29	And try to replace or substitute name Ankit with Ashish
07:35	Watch the video available at the link shown below http://spoken-tutorial.org/What_is_a_Spoken Tutorial
07:39	It summarises the Spoken Tutorial project
07:41	If you do not have good bandwidth, you can download and watch it
07:46	The Spoken Tutorial Project Team Conducts workshops using spoken tutorials
07:52	Gives certificates to those who pass an online test
07:56	For more details, please write to contact@spoken-tutorial.org
08:04	Spoken Tutorial Project is a part of the Talk to a Teacher project
08:07	It is supported by the National Mission on Education through ICT, MHRD, Government of India
08:16	More information on this Mission is available at the link shown below: http://spoken-tutorial.org\NMEICT-Intro
08:22	The script has been contributed by Anirban and Sachin.
08:28	This is Ashwini PAtil from IIT bombay signing off. Thank you for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14