Difference between revisions of "BASH/C2/Globbing-and-Export-statement/English-timed"
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| − | + | |'''Narration''' | |
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|* '''export command''' | |* '''export command''' | ||
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|# '''? (Question mark)''' | |# '''? (Question mark)''' | ||
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|It matches all the files having '''.sh extension''' in the present directory. | |It matches all the files having '''.sh extension''' in the present directory. | ||
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| This will match and display the files starting with letter ''' a''' or '''b '''or '''c.''' | | This will match and display the files starting with letter ''' a''' or '''b '''or '''c.''' | ||
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|But will omit those starting with character as ''''a'''' OR ''''b'''' OR ''''c'''' | |But will omit those starting with character as ''''a'''' OR ''''b'''' OR ''''c'''' | ||
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| Switch to the '''Terminal ''' type, '''myvar equal to sign lion''' press''' Enter.''' | | Switch to the '''Terminal ''' type, '''myvar equal to sign lion''' press''' Enter.''' | ||
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| To go to a new '''Shell''', we can either open a new '''Terminal''' or type, '''slash bin slash bash''' press''' Enter.''' | | To go to a new '''Shell''', we can either open a new '''Terminal''' or type, '''slash bin slash bash''' press''' Enter.''' | ||
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Revision as of 15:29, 27 April 2015
| Time | Narration |
| 00:01 | Welcome to this spoken tutorial on Globbing and Export command |
| 00:06 | In this tutorial, we will learn about |
| 00:08 | * Globbing |
| 00:09 | * export command |
| 00:11 | To follow this tutorial, You should be familiar with Linux Operating System |
| 00:18 | If not, for relevant tutorials please visit our website which is are shown. |
| 00:24 | For this tutorial I am using |
| 00:27 | * Ubuntu Linux 12.04 OS and |
| 00:31 | * GNU Bash version 4.1.10 |
| 00:35 | Please note GNU Bash 'version 4' or above is recommended to practise this tutorial. |
| 00:43 | Let us start with an introduction to globbing. |
| 00:46 | * Filename or pathname expansion carried by BASH is known as Globbing. |
| 00:52 | * Globbing recognizes and expands wildcards. |
| 00:57 | * It also interprets standard wildcard characters like |
| 01:02 | # * (asterix) and |
| 01:04 | # ? (Question mark) |
| 01:05 | Let us understand this with the help of an example. |
| 01:09 | Open the terminal window by pressing Ctrl+Alt and T keys simultaneously on your keyboard. |
| 01:18 | On the Terminal type,ls space asterix dot sh press Enter. |
| 01:27 | It matches all the files having .sh extension in the present directory. |
| 01:34 | Here we can see that all the sh files are listed. |
| 01:40 | Let me clear the prompt,Now type, ls space s asterix dot sh press Enter. |
| 01:51 | We can see that s asterix dot sh matches all the files starting with character s and having sh as extension. |
| 02:02 | Lets move on , |
| 02:04 | Now type, ls space opening square bracket a hyphen c closing square bracket asterix dot sh press Enter. |
| 02:19 | This will match and display the files starting with letter a or b or c. |
| 02:26 | Observe the output. |
| 02:28 | We see a list of all files starting with character a or b or c. |
| 02:35 | And these files have sh extension. |
| 02:39 | Now, let's go ahead and type ls space opening square bracket caret sign a hyphen c closing square bracket asterix dot sh press Enter. |
| 02:55 | This will match all the filenames with extension sh. |
| 03:00 | But will omit those starting with character as 'a' OR 'b' OR 'c' |
| 03:07 | Observe the output. You will notice that the filenames are not starting with character 'a' , 'b' or 'c'. |
| 03:16 | Let me clear the prompt, |
| 03:19 | Now type, ls space opening square bracket capital 'A' small 'a' closing square bracket asterix sign dot sh press Enter. |
| 03:34 | This will match filenames starting with upper and lower case of letter 'A'. |
| 03:40 | See the output.All filenames starting with upper and lower case 'A and extension sh are listed. |
| 03:49 | Now let's see the Export command in BASH. |
| 03:53 | Switch to the slides. |
| 03:55 | In Bash, variables are local to their own Shell. |
| 04:00 | * Local variables can be used by same Shell or by the current Shell. |
| 04:06 | Export command Exports a variable or a function to the environment of all child processes. |
| 04:15 | * Can also change a local variable to a global variable. |
| 04:20 | We will try to understand this with an example. |
| 04:24 | Switch to the Terminal type, myvar equal to sign lion press Enter. |
| 04:34 | Now type, echo space dollar sign myvar press Enter. |
| 04:41 | lion is printed. |
| 04:44 | This is the value assigned to the variable myvar. |
| 04:48 | Now, let's navigate to a new Shell. |
| 04:51 | To go to a new Shell, we can either open a new Terminal or type, slash bin slash bash press Enter. |
| 05:03 | Now let's check the value in the variable myvar. |
| 05:07 | Type, echo space dollar sign myvar press Enter. |
| 05:15 | An empty line is printed. |
| 05:17 | This means that the value assigned to variable myvar was not transferred to this Shell. |
| 05:24 | Also, the variable myvar is local only to the previous Shell and not to current Shell. |
| 05:32 | We will type exit to get back to our previous Shell. |
| 05:36 | So, to declare variables globally, we have to use the export command. |
| 05:43 | Let's learn how. |
| 05:46 | Type, export space myvar equal to sign lion press Enter. |
| 05:55 | Now type, echo space dollar sign myvar press Enter. |
| 06:02 | lion is displayed. |
| 06:05 | Let's navigate to another Shell, type, slash bin slash bash press Enter. |
| 06:13 | Let me clear the prompt. |
| 06:15 | Now type,echo space dollar sign myvar. |
| 06:22 | lion is displayed |
| 06:25 | This is because we have declared the variable myvar globally using the export command. |
| 06:33 | This brings us to the end of this tutorial. |
| 06:36 | Let us summarize. Come back to our slides. |
| 06:39 | In this tutorial we learnt, |
| 06:41 | * Globbing |
| 06:42 | * Export command |
| 06:44 | As an assignment. |
| 06:45 | Write a Bash script to do all the operations discussed under globbing. |
| 06:51 | Watch the video available at the link shown below |
| 06:54 | It summarises the Spoken Tutorial project |
| 06:57 | If you do not have good bandwidth, you can download and watch it |
| 07:02 | The Spoken Tutorial Project Team |
| 07:05 | Conducts workshops using spoken tutorials |
| 07:08 | Gives certificates to those who pass an online test |
| 07:12 | For more details, please write to contact@spoken-tutorial.org |
| 07:20 | Spoken Tutorial Project is a part of the Talk to a Teacher project |
| 07:24 | It is supported by the National Mission on Education through ICT, MHRD, Government of India |
| 07:31 | More information on this Mission is available at the link shown below. |
| 07:37 | The script has been contributed by FOSSEE and Spoken-Tutorial team. |
| 07:42 | This is Ashwini from IIT Bombay Signning off. |
| 07:47 | Thank you for joining. |
