Difference between revisions of "BOSS-Linux/C3/The-sed-command/English-timed"

From Script | Spoken-Tutorial
Jump to: navigation, search
 
(3 intermediate revisions by 2 users not shown)
Line 5: Line 5:
 
|-
 
|-
 
| 00:01
 
| 00:01
−
|  Welcome to this spoken tutorial on the sed - the stream editor.
+
|  Welcome to this spoken tutorial on '''sed''' - the '''stream editor'''.
  
 
|-
 
|-
−
| 00:05
+
| 00:07
−
|  In this tutorial  we will learn usage of '''sed '''command.
+
|  In this tutorial, we will learn usage of '''sed '''command.
  
 
|-
 
|-
 
|  00:11
 
|  00:11
−
|We will do through some examples
+
|We will do through some examples.
  
 
|-
 
|-
Line 21: Line 21:
 
|-
 
|-
 
| 00:16
 
| 00:16
−
|I am using'''Ubuntu Linux''' version 12.04''' Operating System''' and '''GNU BASH''' version 4.2.24
+
|I am using '''Linux''' ''' Operating System''' and '''GNU BASH''' version 4.2.24
  
 
|-
 
|-
Line 28: Line 28:
  
 
|-
 
|-
−
| 00:34
+
| 00:33
−
| As prerequisites
+
| As prerequisites,
  
 
|-
 
|-
−
| 00:36
+
| 00:35
−
|You should know Basics of linux terminal
+
|you should know basics of '''Linux terminal'''.
  
 
|-
 
|-
−
| 00:39
+
| 00:38
−
|For relevant tutorials please visit our website which as shown: http://spoken-tutorial.org  
+
|For relevant tutorials, please visit our website which is as shown: http://spoken-tutorial.org  
  
 
|-
 
|-
−
| 00:45
+
| 00:44
−
| Let us with an introduction to '''sed'''
+
| Let us start with an introduction to '''sed'''.
  
 
|-
 
|-
−
|00:48
+
|00:47
−
|'''sed''' is a stream editor.  
+
|'''sed''' is a '''stream editor'''.  
  
 
|-
 
|-
−
| 00:51
+
| 00:50
 
|'''sed''' finds some pattern of text in a particular location of a file.  
 
|'''sed''' finds some pattern of text in a particular location of a file.  
  
 
|-
 
|-
−
|  00:58
+
|  00:57
−
|It performs some display or editing function
+
|It performs some display or editing function-
  
 
|-
 
|-
−
| 01:02
+
| 01:01
−
|editing function like insertion, substitution and deletion in matched text.
+
|editing functions like insertion, substitution and deletion in matched text.
  
 
|-
 
|-
 
| 01:10
 
| 01:10
−
| Let us first start with some examples.
+
| Let us start with some examples.
  
 
|-
 
|-
Line 68: Line 68:
  
 
|-
 
|-
−
|  01:19
+
|  01:18
−
|I have a file called '''seddemo.txt''' in home directory version.  
+
|I have a file called '''seddemo.txt''' in the '''home''' directory.  
  
−
|-
+
|-
−
| 01:24
+
| 01:23
−
|Let us view its content.
+
|Let us view its contents.
  
 
|-
 
|-
 
|  01:26
 
|  01:26
−
|In this file we have some enteries like roll no, name, stream, marks, pass or fail and the stipend amount.
+
|In this file, we have some entries like- roll no, name, stream, marks, pass or fail and the stipend amount.
  
 
|-
 
|-
−
| 01:39
+
| 01:38
−
|Now suppose we want to print the second line of the file.
+
|Now suppose, we want to print the second line of the file.
  
 
|-
 
|-
−
|  01:44
+
|  01:43
−
|For this we need to oepn the terminal by pressing
+
|For this, we need to open the '''terminal'''.  
−
CTRL + ALT and T keys simultaneously on your keyboard.
+
  
 
|-
 
|-
−
| 01:53
+
| 01:47
−
|Now Type
+
|Now, type:'''sed''' space within  single quotes '''2p''' after the single quotes space '''seddemo.txt'''
  
 
|-
 
|-
−
| 01:55
+
| 01:57
−
|'''sed''' space within  single quotes ‘'''2p’''' after the single quotes space '''seddemo.txt'''
+
|Press '''Enter'''.
  
 
|-
 
|-
−
| 02:03
+
| 02:00
−
|Press '''Enter'''
+
|Here, '''2''' denotes the location which is the second line.
  
 
|-
 
|-
−
| 02:06
+
| 02:05
−
|Here '''2''' denotes the location which is the second line.
+
|'p' denotes the action which is printing.
  
 
|-
 
|-
−
| 02:11
+
| 02:09
−
|'''p''' denotes the action, which is printing('''p''').
+
|Now look at the output.
  
 
|-
 
|-
−
| 02:16
+
| 02:11
−
|Now Look at the output.
+
|It shows the entire file but see that the second line is printed twice.
  
 
|-
 
|-
 
|  02:18
 
|  02:18
−
|It shows the entire file but see that the second line is printed twice.
+
|This is the default behavior of action '''p'''.
  
 
|-
 
|-
−
| 02:25
+
| 02:22
−
|This is the default behaviour of the action '''p'''.
+
|To only print the second line,
  
 
|-
 
|-
−
| 02:29
+
| 02:25
−
|To only print the second line
+
|type: '''sed '''space  '''-n''' space (within single quotes) '''2p''' after the single quotes space '''seddemo.txt '''
  
 
|-
 
|-
−
| 02:31
+
|  02:37
−
|Type
+
−
 
+
−
|-
+
−
|  02:33
+
−
|'''sed '''space  '''-n''' space (Within single quotes) '''2p''' after the single quotes space '''seddemo.txt '''
+
−
 
+
−
|-
+
−
|  02:44
+
 
|Press '''Enter.'''
 
|Press '''Enter.'''
  
 
|-
 
|-
−
|02:46
+
|02:40
−
|We see only the second line as printed.
+
|We see only the second line is printed.
  
 
|-
 
|-
−
| 02:51
+
| 02:44
 
| '''-n''' stands for ‘silent mode’ which will suppress all unnecessary output.
 
| '''-n''' stands for ‘silent mode’ which will suppress all unnecessary output.
  
 
|-
 
|-
−
|  02:58
+
|  02:51
−
|Then we give the location in the stream that we want to edit or display.  
+
|Then we give the location in the '''stream''' that we want to edit or display.  
  
 
|-
 
|-
−
|  03:03
+
|  02:57
 
|We want to select the second line.
 
|We want to select the second line.
  
 
|-
 
|-
−
|  03:07
+
|  03:00
−
|'''p''' indicates the action we want to take ie to print the second line.
+
|'''p''' indicates the action we want to take i.e. to print the second line
  
 
|-
 
|-
−
|  03:12
+
|  03:06
−
|And '''seddemo.txt''' is the name of the file
+
|and '''seddemo.txt''' is the name of the file.
  
 
|-
 
|-
−
|  03:18
+
|  03:11
−
|This is the general syntax of sed command.
+
|This is the general syntax of ''''sed' command'''.
  
 
|-
 
|-
−
| 03:21
+
| 03:15
−
|Now let us print the last line of the file.
+
|Now, let us print the last line of the file.
  
 
|-
 
|-
−
|03:26
+
|03:20
−
|Let me clear the promt
+
|Let me clear the prompt.
  
 
|-
 
|-
−
|  03:29
+
|  03:24
−
|Now Type
+
|Now, type: '''sed''' space  '''-n''' space within single quotes dollar-sign '''p''' after the single quotes space '''seddemo.txt '''
  
 
|-
 
|-
−
| 03:32
+
|  03:36
−
|'''sed''' space  '''-n''' space within single quotes (dollar) '''$p''' after the single quotes space '''seddemo.txt '''
+
−
 
+
−
|-
+
−
|  03:42
+
 
|Press '''Enter'''.
 
|Press '''Enter'''.
  
 
|-
 
|-
−
|  03:43
+
|  03:39
 
|We see that the last line is printed.
 
|We see that the last line is printed.
  
 
|-
 
|-
−
|  03:49
+
|  03:42
−
|Now come back to text editor.
+
|Now come back to '''text editor'''.
  
 
|-
 
|-
−
| 03:51
+
| 03:45
−
| Suppose we want to print the enteries from 3rd to 6th
+
| Suppose, we want to print the entries from 3rd to 6th.
  
 
|-
 
|-
−
| 03:57
+
| 03:50
−
|For this we need to type on the terminal:  
+
|For this, we need to type on the terminal:  
  
 
|-
 
|-
−
|  04:00
+
|  03:54
−
|'''sed''' space  '''-n''' space within single quotes '''3''' (comma) ''',6p’''' space '''seddemo.txt '''
+
|'''sed''' space  '''-n''' space within single quotes '''3''' comma '''6p''' after the single quotes space '''seddemo.txt'''
  
 
|-
 
|-
−
|  04:14
+
|  04:07
−
|'''Press Enter.'''
+
|Press '''Enter.'''
  
 
|-
 
|-
−
|  04:16
+
|  04:09
 
|The output is displayed from the third line to the sixth line.
 
|The output is displayed from the third line to the sixth line.
  
 
|-
 
|-
−
| 04:21
+
| 04:14
−
| Any of the actions can be reversed by using the exclamation mark before the action.
+
| Any of the actions can be reversed by using the exclamation mark (!) before the action.
  
 
|-
 
|-
−
|  04:28
+
|  04:21
−
|Say if we had to print all lines except from 3rd to 6th we will type:
+
|Say, if we had to print all lines except from 3rd to 6th, we will type:'''sed''' space  '''-n''' space within single quotes '''3''' comma '''6''' (exclamation mark) '''!p'''  
−
'''sed''' space  '''-n''' space within single quotes ‘'''3''' (comma) ''',6''' (exclamation mark) '''!p'''  
+
  
 
|-
 
|-
−
| 04:44
+
| 04:38
 
|After the single quotes space '''seddemo.txt '''
 
|After the single quotes space '''seddemo.txt '''
  
 
|-
 
|-
−
|  04:51
+
|  04:45
−
|'''Press''' '''Enter.'''
+
|Press '''Enter.'''The output is displayed.
  
 
|-
 
|-
−
|  04:53
+
|  04:49
−
|The output is displayed.
+
−
 
+
−
|-
+
−
|  04:56
+
 
|Let us switch back to our slides.
 
|Let us switch back to our slides.
  
 
|-
 
|-
−
|  04:58
+
|  04:52
 
|Line addressing and context addressing.
 
|Line addressing and context addressing.
  
 
|-
 
|-
−
| 05:03
+
| 04:56
 
| So far, we specified the lines in the file on which the action needs to be taken.
 
| So far, we specified the lines in the file on which the action needs to be taken.
  
 
|-
 
|-
−
|  05:09
+
|  05:02
−
|This is known as line addressing.
+
|This is known as '''line addressing''';
  
 
|-
 
|-
−
|  05:12
+
|  05:05
−
|Address specified by the line numbers.
+
|address specified by the line numbers.
  
 
|-
 
|-
−
|  05:15
+
|  05:08
 
|This is one way of addressing.
 
|This is one way of addressing.
  
 
|-
 
|-
−
| 05:18
+
| 05:11
−
|Another way of addressing is '''Context addressing'''
+
|Another way of addressing is '''Context addressing'''.
  
 
|-
 
|-
−
|  05:22
+
|  05:16
 
|Lines that contain particular context say a particular word.
 
|Lines that contain particular context say a particular word.
  
 
|-
 
|-
−
|  05:28
+
|  05:21
−
|If we want to take actions on lines that contain a particular word we use context addressing.
+
|If we want to take actions on lines that contain a particular word, we use '''context addressing'''.
  
 
|-
 
|-
−
|  05:36
+
|  05:29
−
|Regular expressions can be used.  
+
|'''Regular expressions''' can be used.  
  
 
|-
 
|-
−
|  05:39
+
|  05:32
 
|Let us see an example.
 
|Let us see an example.
  
 
|-
 
|-
−
|  05:42
+
|  05:35
−
|Come back to our editor.
+
|Come back to our text editor.
  
 
|-
 
|-
−
| 05:44
+
| 05:38
−
|  Say we want to print those lines which have the word '''computers'''.
+
|  Say, we want to print those lines which have the word "computers".
  
 
|-
 
|-
−
|  05:50
+
|  05:44
−
|Come back to our temrinal.
+
|Come back to our terminal.
  
 
|-
 
|-
−
|  05:53
+
|  05:46
−
|Now Type
+
|Now, type:
  
 
|-
 
|-
−
|  05:54
+
|  05:48
−
|'''sed''' space '''-n''' space (within single quotes) (front slash)(opening square bracket) [cC] (Closing Square bracket)  omputers/p after the single quotes'''space '''seddemo.txt '''
+
|'''sed''' space '''-n''' space within single-quotes front-slash opening square-bracket '''[cC]''' closing Square-bracket '''omputers/p''' after the single quotes space '''seddemo.txt '''
  
 
|-
 
|-
−
|  06:20
+
|  06:14
−
|'''Press''' '''Enter.'''
+
|Press '''Enter.'''
  
 
|-
 
|-
−
|  06:23
+
|  06:16
−
|We see the lines with the word computers is displayed.
+
|We see the lines with the word "computers" is displayed.
  
 
|-
 
|-
−
|  06:28
+
|  06:22
−
|We write pattern within square brackets.  
+
|We write pattern within square-brackets.  
  
 
|-
 
|-
−
|  06:31
+
|  06:24
−
|This is to match any one or both of the characters within square brackets.
+
|This is to match any one or both of the characters within square-brackets.
  
 
|-
 
|-
−
| 06:36
+
| 06:30
−
|When we need to match patterns the pattern needs to be typed between front slashes.
+
|When we need to match patterns, the pattern needs to be typed between front slashes.
  
 
|-
 
|-
−
| 06:43
+
| 06:37
−
| We can print it in file as well using the '''w''' option.  
+
| We can print it in a file as well using the '''w''' option. For this, type:
  
 
|-
 
|-
−
|  06:50
+
|  06:44
−
|For this type:
+
|'''sed''' space '''-n''' space within single-quotes front-slash opening square-bracket '''[cC]''' closing square-bracket '''omputers/w''' space '''computer_student.txt''' after the single quotes space '''seddemo.txt'''
  
 
|-
 
|-
−
|  06:52
+
|  07:11
−
|'''sed''' space '''-n''' space (within single quotes) (front slash) (opening square bracket)  '''[cC] (closing square bracket)Computers/w''' space '''computer_student.txt''' after the space '''seddemo.txt '''
+
|Press '''Enter.'''
  
 
|-
 
|-
−
|  07:18
+
|  07:14
−
|'''Press''' '''Enter.'''
+
|Now, all the matching lines would be transferred to the file '''computer_student.txt'''.  
  
 
|-
 
|-
−
| 07:21
+
| 07:21
−
|Now all the matching lines would be transferred to the file '''computer_student.txt'''.  
+
| Let us view the contents.
  
 
|-
 
|-
−
| 07:27
+
| 07:25
−
| Let us view the content of '''computer_student'''
+
| Type: '''cat''' space '''computer_student.txt'''
  
 
|-
 
|-
−
|  07:31
+
|  07:32
−
| Type '''cat''' space '''computer_student'''.txt
+
|Press '''Enter.'''
  
 
|-
 
|-
−
|  07:38
+
|  07:35
−
|'''Press Enter.'''
+
|We see the entries.
  
 
|-
 
|-
−
| 07:42
+
| 07:37
−
|We see the entries
+
−
 
+
−
|-
+
−
| 07:43
+
 
| We can also have patterns that we can write to different files.  
 
| We can also have patterns that we can write to different files.  
  
 
|-
 
|-
−
|  07:50
+
|  07:42
−
| Let us clear the promt
+
| Let us clear the prompt.
  
 
|-
 
|-
−
|  07:52
+
|  07:45
−
| Type '''sed''' space '''-n''' space '''-e''' space (within single quotes) (front slash) '''‘/electronics/w''' space '''electro.txt’''' after the single quotes  '''-e''' space (within single quotes) (front slash) '''‘/civil/w''' space '''civil.txt’''' after the single quote  space '''seddemo.txt '''
+
| Type: '''sed''' space '''-n''' space '''-e''' space (within single quotes) (front slash) '''‘/electronics/w''' space '''electro.txt’''' after the single quotes space '''-e''' space (within single quotes) (front slash) '''‘/civil/w''' space '''civil.txt’''' after the single quote  space '''seddemo.txt'''
  
 
|-
 
|-
−
|  08:24
+
|  08:18
−
|Press '''Enter'''
+
|Press '''Enter'''.
  
 
|-
 
|-
−
|  08:28
+
|  08:22
−
|Here '''-e''' is used to combine multiple methods''' '''
+
|Here, '''-e''' is used to combine multiple methods.
  
 
|-
 
|-
−
|08:34
+
|08:27
−
|This would create two files '''electro.txt''' and '''civil.txt'''.  
+
|This would create two files- '''electro.txt''' and '''civil.txt'''.  
  
 
|-
 
|-
−
|08:41
+
|08:34
−
| To see what they contain type:
+
| To see what they contain, type:
  
 
|-
 
|-
−
|  08:43
+
|  08:37
 
|'''cat '''space''' electro.txt'''  
 
|'''cat '''space''' electro.txt'''  
  
 
|-
 
|-
−
|  08:49
+
|  08:42
−
|This will display the enteries with the word electronics.
+
|This will display the entries with the word "electronics".
  
 
|-
 
|-
−
|  08:54
+
|  08:47
−
|Let us see the content of civil file.
+
|Let us see the content of "civil" file.
  
 
|-
 
|-
−
|  08:58
+
|  08:50
−
| Type '''cat '''space''' civil.txt'''
+
| Type: '''cat '''space''' civil.txt'''
  
 
|-
 
|-
−
|  09:01
+
|  08:55
−
|''' press Enter'''
+
| press '''Enter'''.
  
 
|-
 
|-
−
|  09:03
+
|  08:57
−
|This will display the enteries having the word civil.
+
|This will display the entries having the word "civil".
  
 
|-
 
|-
−
| 09:08
+
| 09:01
 
| We will see some more set of commands in another tutorial.
 
| We will see some more set of commands in another tutorial.
  
 
|-
 
|-
−
|  09:12
+
|  09:05
 
|I will use the same program.
 
|I will use the same program.
  
 
|-
 
|-
−
|09:14
+
|09:08
 
|This brings us to the end of this tutorial.
 
|This brings us to the end of this tutorial.
  
 
|-
 
|-
−
|09:18
+
|09:11
−
|Let us switch back to our slide
+
|Let us switch back to our slide.
  
 
|-
 
|-
−
| 09:20
+
| 09:14
−
| we will  summarize,
+
| we will  summarize.In this tutorial, we learnt: '''sed'''
  
 
|-
 
|-
−
|  09:22
+
|  09:18
−
|In this tutorial we learnt,sed
+
|To print using '''sed.'''Line Addressing.
  
 
|-
 
|-
−
|  09:25
+
|  09:21
−
|To print using sed.
+
|Context Addressing.
  
 
|-
 
|-
−
| 09:26
+
| 09:23
−
|Line Addressing.
+
| As an assignment,
  
 
|-
 
|-
−
|  09:27
+
|  09:25
−
|Context Addressing.
+
|use the same text file "seddemo.txt".
  
 
|-
 
|-
−
| 09:30
+
| 09:28
−
| As an assignment,
+
|Try to print records from 6th to 12th line.
  
 
|-
 
|-
−
| 09:32
+
| 09:33
−
|Use the same text file '''seddemo.txt.'''
+
| Watch the video available at the link shown below.
  
 
|-
 
|-
−
|  09:35
+
|  09:36
−
|Try to print records from 6th to 12th line.
+
|It summarizes the Spoken Tutorial project.
  
 
|-
 
|-
−
| 09:40
+
| 09:39
−
| Watch the video available at the link shown below
+
|If you do not have good bandwidth, you can download and watch it.
  
 
|-
 
|-
−
| 09:42
+
| 09:44
−
|It summarises the Spoken Tutorial project
+
| The Spoken Tutorial project team:
  
 
|-
 
|-
 
|  09:46
 
|  09:46
−
|If you do not have good bandwidth, you can download and watch it
+
|Conducts workshops using spoken tutorials.
  
 
|-
 
|-
−
| 09:51
+
| 09:49
−
| The Spoken Tutorial Project Team
+
|Gives certificates to those who pass an online test.
  
 
|-
 
|-
 
|  09:53
 
|  09:53
−
|Conducts workshops using spoken tutorials
+
|For more details, please write to contact@spoken-tutorial.org
  
 
|-
 
|-
−
| 09:55
+
| 10:00
−
|Gives certificates to those who pass an online test
+
| '''Spoken Tutorial''' project is a part of the '''Talk to a Teacher''' project.
  
 
|-
 
|-
−
|  10:00
+
|  10:04
−
|For more details, please write tocontact@spoken-tutorial.org
+
|It is supported by the National Mission on Education through ICT, MHRD, Government of India.
−
 
+
−
|-
+
−
| 10:07
+
−
|  Spoken Tutorial Project is a part of the Talk to a Teacher project
+
  
 
|-
 
|-
 
|  10:11
 
|  10:11
−
|It is supported by the National Mission on Education through ICT, MHRD, Government of India
+
|More information on this mission is available at: http://spoken-tutorial.org\NMEICT-Intro
−
 
+
−
|-
+
−
|  10:18
+
−
|More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro
+
  
 
|-
 
|-
−
| 10:25
+
| 10:17
−
|This is Ashwini Patil from IIT Bombay signing off . Thank You for joining.
+
|This is Ashwini Patil from IIT Bombay, signing off. Thank You for joining.
  
 
|}
 
|}

Latest revision as of 12:36, 24 March 2017

Time Narration
00:01 Welcome to this spoken tutorial on sed - the stream editor.
00:07 In this tutorial, we will learn usage of sed command.
00:11 We will do through some examples.
00:14 To record this tutorial,
00:16 I am using Linux Operating System and GNU BASH version 4.2.24
00:26 Please note, GNU bash version 4 or above is recommended to practice this tutorial.
00:33 As prerequisites,
00:35 you should know basics of Linux terminal.
00:38 For relevant tutorials, please visit our website which is as shown: http://spoken-tutorial.org
00:44 Let us start with an introduction to sed.
00:47 sed is a stream editor.
00:50 sed finds some pattern of text in a particular location of a file.
00:57 It performs some display or editing function-
01:01 editing functions like insertion, substitution and deletion in matched text.
01:10 Let us start with some examples.
01:13 We will see how to print using the sed command.
01:18 I have a file called seddemo.txt in the home directory.
01:23 Let us view its contents.
01:26 In this file, we have some entries like- roll no, name, stream, marks, pass or fail and the stipend amount.
01:38 Now suppose, we want to print the second line of the file.
01:43 For this, we need to open the terminal.
01:47 Now, type:sed space within single quotes 2p after the single quotes space seddemo.txt
01:57 Press Enter.
02:00 Here, 2 denotes the location which is the second line.
02:05 'p' denotes the action which is printing.
02:09 Now look at the output.
02:11 It shows the entire file but see that the second line is printed twice.
02:18 This is the default behavior of action p.
02:22 To only print the second line,
02:25 type: sed space -n space (within single quotes) 2p after the single quotes space seddemo.txt
02:37 Press Enter.
02:40 We see only the second line is printed.
02:44 -n stands for ‘silent mode’ which will suppress all unnecessary output.
02:51 Then we give the location in the stream that we want to edit or display.
02:57 We want to select the second line.
03:00 p indicates the action we want to take i.e. to print the second line
03:06 and seddemo.txt is the name of the file.
03:11 This is the general syntax of 'sed' command.
03:15 Now, let us print the last line of the file.
03:20 Let me clear the prompt.
03:24 Now, type: sed space -n space within single quotes dollar-sign p after the single quotes space seddemo.txt
03:36 Press Enter.
03:39 We see that the last line is printed.
03:42 Now come back to text editor.
03:45 Suppose, we want to print the entries from 3rd to 6th.
03:50 For this, we need to type on the terminal:
03:54 sed space -n space within single quotes 3 comma 6p after the single quotes space seddemo.txt
04:07 Press Enter.
04:09 The output is displayed from the third line to the sixth line.
04:14 Any of the actions can be reversed by using the exclamation mark (!) before the action.
04:21 Say, if we had to print all lines except from 3rd to 6th, we will type:sed space -n space within single quotes 3 comma 6 (exclamation mark) !p
04:38 After the single quotes space seddemo.txt
04:45 Press Enter.The output is displayed.
04:49 Let us switch back to our slides.
04:52 Line addressing and context addressing.
04:56 So far, we specified the lines in the file on which the action needs to be taken.
05:02 This is known as line addressing;
05:05 address specified by the line numbers.
05:08 This is one way of addressing.
05:11 Another way of addressing is Context addressing.
05:16 Lines that contain particular context say a particular word.
05:21 If we want to take actions on lines that contain a particular word, we use context addressing.
05:29 Regular expressions can be used.
05:32 Let us see an example.
05:35 Come back to our text editor.
05:38 Say, we want to print those lines which have the word "computers".
05:44 Come back to our terminal.
05:46 Now, type:
05:48 sed space -n space within single-quotes front-slash opening square-bracket [cC] closing Square-bracket omputers/p after the single quotes space seddemo.txt
06:14 Press Enter.
06:16 We see the lines with the word "computers" is displayed.
06:22 We write pattern within square-brackets.
06:24 This is to match any one or both of the characters within square-brackets.
06:30 When we need to match patterns, the pattern needs to be typed between front slashes.
06:37 We can print it in a file as well using the w option. For this, type:
06:44 sed space -n space within single-quotes front-slash opening square-bracket [cC] closing square-bracket omputers/w space computer_student.txt after the single quotes space seddemo.txt
07:11 Press Enter.
07:14 Now, all the matching lines would be transferred to the file computer_student.txt.
07:21 Let us view the contents.
07:25 Type: cat space computer_student.txt
07:32 Press Enter.
07:35 We see the entries.
07:37 We can also have patterns that we can write to different files.
07:42 Let us clear the prompt.
07:45 Type: sed space -n space -e space (within single quotes) (front slash) ‘/electronics/w space electro.txt’ after the single quotes space -e space (within single quotes) (front slash) ‘/civil/w space civil.txt’ after the single quote space seddemo.txt
08:18 Press Enter.
08:22 Here, -e is used to combine multiple methods.
08:27 This would create two files- electro.txt and civil.txt.
08:34 To see what they contain, type:
08:37 cat space electro.txt
08:42 This will display the entries with the word "electronics".
08:47 Let us see the content of "civil" file.
08:50 Type: cat space civil.txt
08:55 press Enter.
08:57 This will display the entries having the word "civil".
09:01 We will see some more set of commands in another tutorial.
09:05 I will use the same program.
09:08 This brings us to the end of this tutorial.
09:11 Let us switch back to our slide.
09:14 we will summarize.In this tutorial, we learnt: sed
09:18 To print using sed.Line Addressing.
09:21 Context Addressing.
09:23 As an assignment,
09:25 use the same text file "seddemo.txt".
09:28 Try to print records from 6th to 12th line.
09:33 Watch the video available at the link shown below.
09:36 It summarizes the Spoken Tutorial project.
09:39 If you do not have good bandwidth, you can download and watch it.
09:44 The Spoken Tutorial project team:
09:46 Conducts workshops using spoken tutorials.
09:49 Gives certificates to those who pass an online test.
09:53 For more details, please write to contact@spoken-tutorial.org
10:00 Spoken Tutorial project is a part of the Talk to a Teacher project.
10:04 It is supported by the National Mission on Education through ICT, MHRD, Government of India.
10:11 More information on this mission is available at: http://spoken-tutorial.org\NMEICT-Intro
10:17 This is Ashwini Patil from IIT Bombay, signing off. Thank You for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14

Retrieved from "https://script.spoken-tutorial.org/index.php?title=BOSS-Linux/C3/The-sed-command/English-timed&oldid=33933"