Difference between revisions of "Linux/C3/More-on-sed-command/English-timed"
From Script | Spoken-Tutorial
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| − | | 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''' | + | | 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''' | ||
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| − | | 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''' | + | | 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''' | ||
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| Along with '''Student Information''' we also want to add '''academics''' in the next year. | | Along with '''Student Information''' we also want to add '''academics''' in the next year. | ||
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Revision as of 17:43, 22 July 2014
| 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. |
