BOSS-Linux/C2/Working-with-Regular-Files/English-timed - Revision history

Pratik kamble at 06:23, 24 March 2017

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Pratik kamble at 06:16, 24 March 2017

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Sandhya.np14 at 07:10, 11 August 2015

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Sandhya.np14 at 06:18, 11 August 2015

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Sandhya.np14 at 05:15, 11 August 2015

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PoojaMoolya at 08:34, 4 December 2014

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PoojaMoolya at 08:34, 4 December 2014

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PoojaMoolya: Created page with "{| border=1 |'''Time''' |'''Narration''' |- | 00:00 |Welcome to this spoken tutorial on working with regular files in Linux. |- | 00:07 |Files and directories together form..."

2014-12-01T10:25:35Z

Created page with "{| border=1 |'''Time''' |'''Narration''' |- | 00:00 |Welcome to this spoken tutorial on working with regular files in Linux. |- | 00:07 |Files and directories together form..."

New page

{| border=1
|'''Time'''
|'''Narration'''
|-
| 00:00
|Welcome to this spoken tutorial on working with regular files in Linux.

|-
| 00:07
|Files and directories together form the Linux File System.

|-
| 00:13
|In a previous tutorial we have already seen how to work with directories. You can find the tutorial at this website.

|-
| 00:25
|In this tutorial we will see how to handle regular files.

|-
| 00:32
|We have already seen in another tutorial how we can create a file using the '''cat''' command. For details please visit this website.

|-
| 00:46
|Let us see how to copy a file from one place to another. For this we have the '''cp''' command.

|-
| 00:56
|Let us see how the command is used.

|-
| 01:00
|To copy a single file we type '''cp''' space one or more of the [OPTION]... space the name of the SOURCE file space the name of the destination file

|-
| 01:15
|To copy multiple files at the same time. We write cp space one or more of the [OPTION]...the name of the SOURCE... files that we want to copy and the name of the destination DIRECTORY in which these files would be copied.

|-
| 01:34
|Let us now see an Example. First we open a terminal.

|-
| 01:42
|We already have a file named test1 in home directory

|-
| 01:49
|To see what is in '''test1'''.We type $ '''cat space test1''' and press enter.

|-
| 02:00
|As we can see the content of '''test1''' is shown, now if we want to copy it into another file called '''test2''' we would write.

'''$ cp space test1 space test2''' and press enter.

|-
| 02:22
|Now the file has been copied.

|-
| 02:25
|If '''test2''' doesn't exist it would be first created and then the content of '''test1''' will be copied to it.

|-
| 02:35
|If it already existed then it would be silently overwritten.To see the copied file type

''' cat test2''' and press enter.

|-
| 02:52
|We can also copy files from and to different directories.For example.

Type ''' cp space /home/anirban/arc/demo1''' which is the name of the file that we want to copy space ''' /home/anirban/demo2''' and press enter.

|-
| 03:32
|What this will do is that it will copy the file '''demo1''' from source diretory '''/home/anirban/arc/''' to the destination directory '''/home/anirban''' it will copy to a file name is '''demo2.'''

|-
| 03:51
|To see that the demo2 is there type '''ls space /home/anirban''' and press enter.

|-
| 04:07
|And as you can see here is '''demo2.'''

|-
| 04:12
|Before moving a head let us clear the screen.

|-
| 04:17
|If you want the file to have the same name in the destination directory, you may not even mention the file name.For example

|-
| 04:27
|Type '''cp space /home/anirban/arc/demo1 space /home/anirban/''' and press enter.

|-
| 04:55
|This will again copy the file '''demo1''' presenting the '''/home/anirban/arc/ '''directory to '''/home/anirban''' directory to a file whose name will be '''demo1''' as well.

|-
| 05:11
|As before to see the '''demo1''' type '''ls/home/anirban''' and press enter.

|-
| 05:25
| And as you can see the '''demo1''' file is there.

|-
| 05:30
|Again before moving a head let us clear the screen.

|-
| 05:37
|Another instance when we do not need to give the destination file name is when we want to copy multiple files.

|-
| 05:44
|We assume that we have three files named '''test1 test2 test3''' in our home directory.

|-
| 05:53
|Now we type ''' cp space test1 space test2 space test3 space /home/anirban/testdir''' and press enter.

|-
| 06:16
|This will copy all the three files named '''test1,test2''' and '''test3''' to the directory ''' /home/anirban/testdir''' without changing their names.

|-
| 06:30
|You see that this files have actually been copied.We will type '''ls space /home/anirban/testdir''' and press enter.

|-
| 06:52
|As you can see '''test1,test2''' and '''test3''' are present in this directory.

|-
| 06:58
|There are many options that go with '''cp'''. Here we will see only the most important of them.

|-
| 07:07
|Let us first will go back to the slides.

|-
| 07:12
|Among the options -R (The capital R) is an important one. It causes recursive copying of an entire directory structure.

|-
| 07:23
|Let us see an example.

|-
| 07:27
|Let us try to copy all the contents of the testdir directory to a directory called test.

|-
| 07:36
|For that we would type cp space testdir slash test and press enter.

|-
| 07:51
|As you can see from the output message.

|-
| 07:54
|Normally we cannot copy a directory having a some content directly with '''cp'' command.

|-
| 08:02
|But using the -R (mius R ) option we can do this.

|-
| 08:07
|Now we type ''' cp space -R(minus capital R) space testdir/ test''' and press enter.

|-
| 08:25
|The files have now been copied, to see that the test directory actually exist type ls and press enter.

|-
| 08:37
|As you can see the test directory exists. Let us clear the screen.

|-
| 08:45
|To see the contents inside test type '''ls test''' and press enter.

|-
| 08:57
|You can see the contents of the test directory.

|-
| 09:01
|Now we go back to the slides.

|-
| 09:05
|We have seen if a file is copied to another file that already exists the existing file is overwritten.

|-
| 09:14
|Now what if we inadvertently overwrite an important file?

|-
| 09:19
|To prevent anything like this to occur, we have the -b option.

|-
| 09:25
|This makes a backup of each exiting destination file.

|-
| 09:32
|We can also use the -i(interactive)option, this always warns us before overwriting any destination file.

|-
| 09:43
|Now let us see how the '''mv''' command works.

|-
| 09:47
|This is used for moving files. Now how is that useful?

|-
| 09:53
|It has two major uses.

|-
| 09:57
|It is used for rename a file or directory.

|-
| 10:00
|It also moves a group of files to a different directory.

|-
| 10:05
|'''mv''' is very similar to '''cp''' which we have already seen. So let us quickly see how mv can be used.

|-
| 10:17
|We open the terminal and type '''mv space test1 space test2''' and press enter.

|-
| 10:32
|This will rename the file named '''test1''' which was already present in the home directory to a file named '''test2.'''

|-
| 10:40
|If '''test2''' already existed then it would be overwritten silently.

|-
| 10:49
|If we want our warning before the file is overwritten.

|-
| 10:54
|We can use the ''' -i ''' option with the mv command.

|-
| 10:59
|Say we have another file named anirban. This file we also want to renew as test2

|-
| 11:08
|We will type ''' mv space -i space anirban space test2''' and press enter.

|-
| 11:21
|As you can see a warning is provided asking whether '''test2''' should be overwritten or not.

|-
| 11:30
|If we press y and then press enter, the file would be actually overwritten.

|-
| 11:37
|Like cp we can use mv with multiple files but in that case the destination should be a directory.

|-
| 11:47
|Before moving ahead let us clear the screen.

|-
| 11:52
|Suppose we have 3 files named ''' abc.txt, pop.txt''' and '''push.txt''' in our home directory.

|-
| 12:03
|To see there presence type ''' ls''' and press enter.

|-
| 12:09
|Here are the files ''' pop.txt, push.txt''' and '''abc.txt''' Let us clear the screen.

|-
| 12:24
|Now we want to move this three files to a directory called '''testdir.'''

|-
| 12:32
|What we need to do is type ''' mv space abc.txt pop.txt push.txt''' and then the name of the destination folder which is '''testdir''' and press enter.

|-
| 12:58
|To see them type ''' ls testdir ''' and press enter.

|-
| 13:06
|You can see the files ''' abc, pop''' and '''push.txt.'''

|-
| 13:14
|Now let us see some options that go with '''mv''''. Let us first go back to the slides.

|-
| 13:22
|Then -b or –backup option is present with the '''mv''' command.It will backup every file in the destination before it is overwritten.

|-
| 13:34
|The -i(minus i) option that we have already seen warns us before overwriting any destination file.

|-
| 13:44
|The next command we will see is the '''rm''' command. This command is used for deleting files.

|-
| 13:52
|Go back to the terminal and type '''ls testdir.'''

|-
| 14:00
|We can see a file name '''faq.txt''' present. Say we want to delete it.

|-
| 14:09
|For this we type ''' rm space testdir/faq.txt''' and press enter.

|-
| 14:23
|This command will remove the file '''faq.txt''' from the '''/testdir''' directory.

|-
| 14:32
|To see that the file has been actually removed or not. Let us again press ''' ls testdir''' and press enter.

|-
| 14:47
|We can no longer see the file ''' faq.txt.'''

|-
| 14:51
|We can use the '''rm''' command with multiple files as well.

|-
| 14:57
|The ''' testdir''' directory contains two files '''abc2''' and '''abc1.'''

|-
| 15:03
|Suppose we want to remove this files '''abc1''' and '''abc2.'''

|-
| 15:09
|For this we would type ''' rm space testdir/abc1 space testdir/abc2''' and press enter.

|-
| 15:31
|This remove the files '''abc1''' and '''abc2''' from '''testdir''' directory.

|-
| 15:39
|To see that they have been removed type '''ls space testdir''' again.You can no longer see '''abc1'''' and '''abc2.'''

|-
| 15:53
|Let us clear the screen before moving ahead.

|-
| 15:58
|Now let us go back to the slides.

|-
| 16:02
|Let us summarize what we just said?

|-
| 16:04
|That is do delete a single file we write '''rm''' and than the name of the file.

|-
| 16:11
|To delete multiple files we write '''rm''' and the name of the multiple files that we want to delete.

|-
| 16:19
|Now let us look into some of the options of the '''rm''' command.

|-
| 16:24
|Sometimes a file is write protected,using '''rm''' will not delete the file then. In this case we have the '''-f''' option which can be used to force delete a file.

|-
| 16:41
|The other common option is the '''-r''' option. Let us see where this options are useful?

|-
| 16:52
|Let us switch back to the terminal.

|-
| 16:57
|'''rm''' command is not normally used for deleting directories, for that we have the rmdir command.

|-
| 17:05
|But '''rmdir''' command normally deletes a directory only then it is empty.

|-
| 17:12
|What if we want to delete a directory that has a number of files and subdirectories inside.

|-
| 17:19
|Let us try the '''rm''' command to do this.

|-
| 17:23
|Let us type '''rm''' and the directory that we want to delete which is '''testdir''' and press enter.

|-
| 17:31
|From the output message we can see that we can not use the '''rm''' directory to delete testdir.

|-
| 17:39
|But if we combine the -r and -f option then we can do this.

|-
| 17:47
|Press ''' rm -rf testdir''' and then press enter.

|-
| 18:00
|Now the '''testdir''' directory has been successfully deleted.

|-
| 18:06
|Let us now go back to the slides to study the next command.

|-
| 18:11
|The '''cmp''' command.

|-
| 18:13
|Sometimes we need to check whether two files are same. If they are same then we may delete one of them.

|-
| 18:22
|Also we may want to see whether a file has changed since the last version.

|-
| 18:28
|For these and many other purposes we can use the '''cmp''' command.

|-
| 18:33
|It compares two files byte by byte.

|-
| 18:38
|To compare file1 and file2 we would write '''cmp file1 file2.'''

|-
| 18: 47
|If the two files have exactly same content then no message would be shown.

|-
| 18:55
|Only the prompt will be printed.

|-
| 18:58
|If there are differences in their contents then the location of the first mismatch will be printed on the terminal.

|-
| 19:10
|Let us see how '''cmp''' works.We have two files named '''sample1''' and '''sample2''' in our home directory.

|-
| 19:19
|Let us see what they contain?

|-
| 19:22
|Type '''cat sample1''' and press enter. It contains the text '''This is a Linux file to test the cmp command'''

|-
| 19:34
|The other file '''sample2''' will contain the text and to see that we will type '''cat sample2''' and press enter.

|-
| 19:44
|It will contain the text '''This is a Unix file to test the cmp command.'''

|-
| 19:50
|Now we would apply the '''cmp''' command on this two files.

|-
| 19:55
|We will write '''cmp space sample1 space sample2''' and press enter.

|-
| 20:08
|As we can see the first difference between the two files '''sample1''' and '''sample2''' is pointed out.

|-
| 20:16
|Let us clear the screen before moving ahead to the next command.

|-
| 20:22
|The next command we will see is the '''wc''' command.

|-
| 20:26
|This command is used to count the number of characters, words and lines in a file.

|-
| 20:34
|We have a file named '''sample3''' in our home directory.

|-
| 20:39
|Let us see its content, for that we will type '''cat space sample3''' and press enter.

|-
| 20:50
|This is the content of '''sample3.'''

|-
| 20:54
|Now let us use the wc command on this file.

|-
| 20:59
|For that we would write '''wc sample3''' and press enter.

|-
| 21:10
|These command points out that the file has 6 lines, 67 words and 385 characters.

|-
| 21:22
|These were some of the commands that help us to work with files.

|-
| 21:27
|There are many more commands. Moreover each of the command that we saw has many other options.

|-
| 21:36
|I encourage you to see more about them using the '''man''' command.

|-
| 21:44
|This brings me to the end of this tutorial at last.

|-
| 21:48
| Spoken Tutorial Project is a part of the Talk to a Teacher project, supported by the National Mission on Education through ICT, MHRD, Government of India.

|-
| 22:02
|More information on the same is available at the following link http://spoken-tutorial.org/NMEICT-Intro.

|-
| 22:18
|This is Anirban signing off . Thanks for joining.

@@ Line 472: / Line 472: @@
 |-
-| 18:38
+|18:38
 |To compare 'file1' and 'file2', we would write '''cmp space file1 space file2.'''
 |-
-| 18: 47
+|18:47
 |If the two files have exactly the same contents then no message would be shown.
@@ Line 484: / Line 484: @@
 |-
-| 18:58
+|18:58
 |If there are differences in their contents then the location of the first mismatch will be printed on the '''terminal'''.
@@ Line 496: / Line 496: @@
 |-
-| 19:22
+|19:22
 |Type: '''cat sample1''' and press '''Enter'''. It contains the text- '''"This is a Linux file to test the cmp command"'''.
 |-
-| 19:34
+|19:34
 |The other file '''sample2''' will contain the text and to see that we will type: '''cat sample2''' and press '''Enter'''.

@@ Line 135: / Line 135: @@
 | 06:52
 |As you can see '''test1,test2''' and '''test3''' are present in this directory.
 |-

@@ Line 319: / Line 319: @@
 |-
 | 13:22
-|Then -b or –backup option is present with the '''mv''' command. It will backup every file in the destination before it is overwritten.
+|The  '-b' or '–backup' option is present with the '''mv''' command. It will backup every file in the destination before it is overwritten.
 |-
 | 13:34
-|The -i(minus i) option that we have already seen, warns us before overwriting any destination file.
+|The '-i' (minus i) option that we have already seen, warns us before overwriting any destination file.
 |-
@@ Line 347: / Line 347: @@
 |-
 | 14:32
-|To see that the file has been actually removed or not, let us again press ''' ls testdir''' and press '''Enter'''.
+|To see that the file has been actually removed or not, let us again press ''' ls space testdir''' and press '''Enter'''.
 |-
@@ Line 383: / Line 383: @@
 |-
 | 15:58
-|Now let us go back to the slides.
+|Now, let us go back to the slides.
 |-
@@ Line 399: / Line 399: @@
 |-
 | 16:19
-|Now let us look into some of the options of the '''rm''' command.
+|Now, let us look into some of the options of the '''rm''' command.
 |-
@@ Line 407: / Line 407: @@
 |-
 | 16:41
-|The other common option is the '''-r''' option. Let us see where this option is useful?
+|The other common option is the '''-r''' option. Let us see where these option are  useful?
 |-
@@ Line 423: / Line 423: @@
 |-
 | 17:12
-|What if we want to delete a directory that has a number of files and sub-directories inside.
+|What if we want to delete a directory that has a number of files and sub-directories inside?
 |-
@@ Line 434: / Line 434: @@
 |-
 | 17:31
-|From the output message, we can see that we can not use the '''rm''' directory to delete testdir.
+|From the output message, we can see that we can not use the '''rm''' directory to delete 'testdir'.
 |-
 | 17:39
-|But if we combine the -r and -f option then we can do this.
+|But if we combine the '-r' and '-f' options then we can do this.
 |-
@@ Line 446: / Line 446: @@
 |-
 | 18:00
-|Now the '''testdir''' directory has been successfully deleted.
+|Now, the '''testdir''' directory has been successfully deleted.
 |-
 | 18:06
-|Let us now go back to the slides to study the next command.
+|Let us now go back to the slides to study the next command-
 |-
 | 18:11
-|The '''cmp''' command-
+|the '''cmp''' command.
 |-
@@ Line 466: / Line 466: @@
 |-
 | 18:28
-|For these and many other purposes we can use the '''cmp''' command.
+|For these and many other purposes, we can use the '''cmp''' command.
 |-
@@ Line 474: / Line 474: @@
 |-
 | 18:38
-|To compare 'file1' and 'file2', we would write '''cmp file1 file2.'''
+|To compare 'file1' and 'file2', we would write '''cmp space file1 space file2.'''
 |-
 | 18: 47
-|If the two files have exactly same content then no message would be shown.
+|If the two files have exactly the same contents then no message would be shown.
 |-
@@ Line 486: / Line 486: @@
 |-
 | 18:58
-|If there are differences in their contents then the location of the first mismatch will be printed on the terminal.
+|If there are differences in their contents then the location of the first mismatch will be printed on the '''terminal'''.
 |-
@@ Line 550: / Line 550: @@
 |-
 | 20:59
-|For that, we would write '''wc sample3''' and press '''Enter'''.
+|For that, we would write '''wc space sample3''' and press '''Enter'''.
 |-