BOSS-Linux/C3/More-on-grep-command/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on more on grep
00:05	In this tutorial we will learn
00:07	some more on grep commands.
00:10	Through some examples
00:13	To record this tutorial, I am using
00:16	Linux Operating System and
00:20	GNU BASH version 4.2.24
00:23	Please note, GNU bash version 4 or above is recommended to practice this tutorial.
00:29	As prerequisites
00:31	You should know Basics of linux terminal.
00:35	You should be aware of grep.
00:37	For relevant tutorials please visit our website which is as shown: http://spoken-tutorial.org
00:43	We can match more than one patterns as well.
00:47	Then we have to use the hyphen e option.
00:52	I will use the same file grepdemo.txt
00:57	Say we want to find information for those who are either in civil or electronics.
01:04	We need to type on the terminal:
01:07	grep space hyphen e space within double quotes electronics after the quotes space hyphen e space within double quotes civil after the quotes space grepdemo.txt
01:22	Press Enter.
01:24	The output is displayed.
01:27	Say you need to look into people whose title is choudhury.
01:32	The problem is different peoples spell their titles in different way.
01:38	So what is the solution?.
01:41	In such cases we can use hyphen e option with hyphen i.
01:47	Type: grep space hyphen ie space in double quotes chaudhury('c' 'h' 'a' 'u' 'd' 'h' 'u' 'r' 'y') after the quotes space hyphen ie space within double quotes chowdhari ('c' 'h' 'o' 'w' 'd' 'h' 'a' 'r' 'i')after the quotes space grepdemo.txt
02:11	Press Enter.
02:14	The output is displayed.
02:16	But there can be many other ways in which we can write the names.
02:22	How many hyphen e options can we give.
02:26	Obviously there needs to be a better way and that way is through Regular expressions.
02:33	A regular expression provides a concise and flexible means for matching strings of text.
02:41	Such as particular characters, words or patterns of characters.
02:47	There are a number of regular expression characters.
02:51	Let us see them one by one.
02:54	The character class.
02:56	It allows us to specify a group of characters within a pair of square brackets .
03:03	Only one out of this group of characters is matched.
03:07	Eg. [abc] would mean that this regular expression matches either a or b or c.
03:17	To match chaudhury we may type at the prompt
03:22	grep space hyphen i space within double quotes ch opening square bracket ao closing square bracket opening square bracket uw closing square bracket dh opening square bracket ua closing square bracket r opening square bracket yi closing square bracket after the double quotes space grepdemo.txt
03:53	Press Enter.
03:55	The output is displayed.
03:59	It still does not match choudhuree with double e.
04:02	If we want to specify a large range then we write:
04:07	First letter dash last letter of the range
04:13	Suppose we like to match any digit we simply write [0-9].
04:20	One out of this group of characters is matched.
04:24	The Asterisk: The asterisk refers to 0 or more occurrences of the immediately preceding character.
04:33	For example ab asterisk can match a,ab,abb,abbb etc.
04:43	So to match the students name whose name is Mira
04:47	We type at the prompt:
04:50	grep space hyphen i space within double quotes m opening square bracket ei closing square bracket asterisk r a a asterisk after the quotes space grepdemo.txt
05:11	Press Enter.
05:13	The output is displayed.
05:16	The dot regular expression matches any one character.
05:21	Say we want to search any words that are 4 letters long and starts with M.
05:27	We would simply type
05:30	grep space within double quotes M... space after the quotes space grepdemo.txt
05:43	Press Enter.
05:45	The output is displayed.
05:47	Here the space within the quotes is important as it would match 5 or more letter words.
05:56	We may be specific about where in the line we want to search for our pattern.
06:01	It may be at the beginning of the line.
06:04	For that we have the caret sign.
06:07	Now if we want get those entries whose roll numbers start with A.
06:13	We know that roll is the first field in the file.
06:18	We type at the prompt: grep within double quotes caret sign A after the quotes grepdemo.txt
06:29	Press Enter.
06:31	The output is displayed.
06:34	Similarly to match a pattern at the end of the file, we have the dollar sign.
06:40	To find stipends between 7000 to 8999 we have to write:
06:49	grep space within double quotesopening square bracket 78 closing square bracket ...dollar sign after the quotes space grepdemo.txt
07:05	Press Enter
07:07	The output is displayed.
07:10	This brings us to the end of this tutorial.
07:13	Let us summarize.
07:15	In this tutorial we learnt,
07:17	To match more than one pattern
07:20	To check a word that has different spelling
07:23	Character class
07:24	The use of asterisk
07:27	To match any one character using dot
07:31	To match a pattern at the beginning of the file
07:35	To match a pattern at the end of the file
07:39	As an assignment, List those entries that are 5 letters long and starts with Y.
07:46	Watch the video available at the link shown below
07:50	It summarises the Spoken Tutorial project
07:53	If you do not have good bandwidth, you can download and watch it
07:59	The Spoken Tutorial Project Team conducts workshops using spoken tutorials
08:04	Gives certificates to those who pass an online test
08:08	For more details, please write to contact@spoken-tutorial.org
08:14	Spoken Tutorial Project is a part of the Talk to a Teacher project
08:19	It is supported by the National Mission on Education through ICT, MHRD, Government of India
08:26	More information on this Mission is available at the link shown below : http://spoken-tutorial.org\NMEICT-Intro
08:32	The script has been contributed by Anirban and Sachin.
08:36	This is Ashwini Patil from IIT Bombay signning off. Thank you for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14