BASH/C2/Globbing-and-Export-statement/English-timed

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 as 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 practice 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	# * (asterisk) 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 asterisk 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 asterisk dot sh press Enter.
01:51	We can see that s asterisk dot sh matches all the files starting with character s and having sh as extension.
02:02	Let's move on ...
02:04	Now, type: ls space opening square bracket a hyphen c closing square bracket asterisk 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 asterisk dot sh press Enter.
02:55	This will match all the file-names 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 file names 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 asterisk sign dot sh press Enter.
03:34	This will match file names starting with upper and lower case of letter 'A'.
03:40	See the output. All file names 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 summarizes 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, signing off.
07:47	Thank you for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Ranjana, Sandhya.np14