BOSS-Linux/C3/The-grep-command/English-timed

Time	Narration
00:01	Welcome to the spoken tutorial on grep command
00:05	In this tutorial we will learn grep command.
00:09	We will do this with the help of some examples.
00:12	To record this tutorial, I am using
00:15	* Linux Operating System
00:18	and *GNU BASH version 4.2.24
00:22	Please note, GNU bash version 4 or above is recommended to practise this tutorial.
00:30	As prerequisites You should know basics of Linux terminal
00:34	For relevant tutorials, please visit our website which is as shown.
00:39	First let us know about regular expressions.
00:43	*Regular expressions are pattern matching techniques.
00:47	*When we have to find out whether a pattern exist in a line, paragraph or a file.
00:54	For ex. If you want to search a phone number in the telephone directory
01:01	Or To find a keyword in a paragraph or a line, we use grep command Let us move on to grep.
01:08	grep searches for one or more patterns in one or more line, paragraph or a file.
01:15	If filename is not mentioned, grep search for the patterns in the standard input.
01:22	If filename is missing, grep searches for the patterns in the standard input.
01:28	I will demonstrate usage of grep using a demo file called grepdemo.txt
01:35	Let us see the content of the file.
01:37	This is a file that has 13 entries.
01:41	Each entry has 6 fields roll number, name, stream, marks, and stipend amount.
01:50	The fields are separated by a bar, which is called a delimiter.
01:55	Let us see how grep works.
01:58	Say we want to use grep command, to see who are the students in the computers stream.
02:04	For this we have to open the terminal.
02:07	Now type on the terminal:
02:09	grep space (within double quotes) computers after the double quotes space grepdemo .txt
02:18	Press Enter
02:20	This would enlist those entries where stream is computers.
02:25	Now compare the result with the original file.
02:29	Come back to our text editor.
02:31	We see that the entry for Zubin is not enlisted.
02:37	Why this is so?
02:38	This is because grep searched for the pattern “computers” with small c
02:43	While for Zubin, the stream is “Computers” with a capital C.
02:48	The pattern matching is case sensitive.
02:51	To make it case insensitive, we need to use the minus i option with grep.
02:58	Come back to our terminal Now Type: grep space (minus) i space (within double quotes) “computers” after the double quotes space grepdemo.txt
03:12	Press Enter.
03:13	This will now enlist all the four entries.
03:17	So we saw, grep enlists only those lines of files that match a given pattern.
03:23	We may do the reverse.
03:26	It is possible to make grep enlist only those lines that do not match the pattern.
03:32	For that we have the minus v option.
03:35	Say, we want to enlist those entries of students who have not passed.
03:40	We can also store this result in another file
03:43	For this type: grep space minus iv space Within double quotes pass after the double quotes space grepdemo.txt space greater than sign space notpass.txt
04:02	Press Enter.
04:04	To see the content of file, type: cat space notpass.txt
04:11	Press Enter.
04:12	The output is displayed.
04:15	Now at the prompt type:
04:17	grep space minus i space' within double quotes fail after the double quotes space grepdemo.txt
04:28	And Press Enter.
04:30	This is different.
04:32	This will include those students who are failed but their result is incomplete.
04:37	If we want to see the line number in the file at which the enlisted entries are, we have the minus n option
04:46	Let us clear the prompt.
04:49	Now type "grep space -in space within double quote "fail" after the double quotes space grepdemo.txt
05:01	Press Enter.
05:03	The line number is displayed.
05:06	The patterns so far have been of single word.
05:10	We may have multiword patterns as well.
05:13	But the entire pattern must be within quotes.
05:17	So type: grep space minus i spacewithin double quotes ankit space saraf after the double quotes space grepdemo.txt
05:29	Press Enter.
05:31	We see that Ankit Saraf's record is displayed.
05:35	We can also find patterns in multiple files.
05:39	For this Type: grep space minus i space within double quotes fail after double quotes space grepdemo.txt space notpass.txt
05:55	Press Enter.
05:57	The output is displayed.
05:59	With multiple files, grep will write the name of the file in which the entry was found.grepdemo.txt and notpass.txt
06:10	These are the records from notpass.txt file and these are the records from grepdemo.txt file.
06:18	Suppose we may only want to know the number of matches or count .
06:23	For that, we have the minus c option
06:27	So Type: grep space minus c spacewithin double quotes Fail with a capital F after the quotes space grepdemo.txt
06:40	Press Enter.
06:42	This will give us the count of number of lines matched.
06:46	This brings us to the end of this tutorial.
06:51	Let us summarize.
06:53	In this tutorial we learnt,
06:55	*To see the content of a file eg. cat filename
06:59	*To list the entries of a particular stream eg. grep “computers” grepdemo.txt
07:06	*To ignore cases eg. grep -i “computers” grepdemo.txt
07:14	*Lines that do not match the pattern eg. grep -iv “pass” grepdemo.txt
07:22	*To list the line numbers with the entries eg. grep -in “fail” grepdemo.txt
07:31	*To store the result in another file eg. grep -iv “pass” grepdemo.txt > notpass.txt
07:41	And*To know the count eg. grep -c “Fail” grepdemo.txt
07:48	As an assignment,
07:50	Explore some other commands like -E, + and ?
07:56	Watch the video available at the link shown below.
07:58	It summarises the Spoken Tutorial project.
08:01	If you do not have good bandwidth, you can download and watch it.
08:05	The Spoken Tutorial Project Team
08:07	*Conducts workshops using spoken tutorials
08:11	*Gives certificates to those who pass an online test
08:14	For more details, please write to contact@spoken-tutorial.org
08:21	Spoken Tutorial Project is a part of the Talk to a Teacher project
08:25	It is supported by the National Mission on Education through ICT, MHRD, Government of India
08:32	More information on this Mission is available at: http://spoken-tutorial.org\NMEICT-Intro
08:36	This is Ashwini Patil from IIT Bombay signning off. Thank you for joining.

Contributors and Content Editors

PoojaMoolya, Pratik kamble, Sandhya.np14