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	*Ubuntu Linux version 12.04 Operating System and
00:20	*GNU BASH version 4.2.24
00:24	Please note, GNU Bash version 4 or above is recommended to practice this tutorial.
00:32	As prerequisites,
00:34	You should know basics of Linux terminal.
00:37	You should be aware of sed tool.
00:40	For relevant tutorials please visit our website which as shown: http://spoken-tutorial.org
00:46	The major use of sed is substitution.
00:49	Replacing some pattern in the input with something else.
00:55	Let's first look at the original file seddemo.txt
01:01	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’
01:16	Type on the terminal
01:18	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
01:40	Press Enter.
01:43	Notice the fourth line.
01:46	Only the first occurrence of Kumar is changed to Roy, not the second one.
01:52	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.
02:03	This is because, by default, the first matched entry of any line is substituted.
02:11	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.
02:48	We can make multiple substitutions in one go as well.
02:53	Say we want to replace the words electronics with the word electrical
02:58	And civil with metallurgy in the file seddemo.txt
03:04	Let me clear the prompt
03:07	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
03:37	And press Enter.
03:39	You can see that the words are replaced.
03:43	Now we want to change the stream of Anirban from computers to mathematics.
03:49	In such case we would need to type:
03:54	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.
04:14	We see that the stream is changed.
04:17	Let us understand what this is.
04:21	First we write sed then in single quotes we write the pattern to be matched.
04:28	This is Anirban.
04:30	Now after the slash comes the operation.
04:34	This is s that stands for substitution, as we have already seen.
04:41	Then we mention the pattern to be replaced which is computers.
04:47	Then the new word that would be substituted, which is mathematics.
04:53	We can also use sed to add or delete lines in the file.
05:00	Say we want to select those lines which do not have stream as electronics.
05:06	For that, we have the d flag.
05:10	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
05:31	Press Enter.
05:33	To see the contents, type: cat space nonelectronics.txt
05:43	Say, at the start of the file we want to add a line Student Information.
05:49	For that we have the i action.
05:54	We need to type: sed space in single quotes '1i space Student Information' after the quote seddemo.txt
06:10	And press Enter.
06:13	You can see the output.
06:15	In fact, we can enter multiple lines like this.
06:20	Say, we want to add the two lines we would do it in a similar way.
06:26	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
06:55	Press Enter
06:57	Notice slash n between the string ‘Information’ and ‘2013’.
07:05	slash n prints 2013 in the next line after ‘Student Information’
07:12	This brings me to the end of this tutorial.
07:14	Let us summarize,
07:17	In this tutorial we learnt,
07:19	Substitution
07:20	Replacement
07:21	And Insertion
07:24	As an assignment, Use the same text file seddemo.txt
07:30	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
07:42	If you do not have good bandwidth, you can download and watch it
07:47	The Spoken Tutorial Project Team Conducts workshops using spoken tutorials
07:53	Gives certificates to those who pass an online test
07:57	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
08:09	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