Question

Project 3-7
In this hands-on project, you use the grep and egrep commands alongside regular ex pression
metacharacters to ex plore the contents of tex t files.
1. Switch to a command-line terminal (tty2) by pressing Ctrl+Alt+F2 and log in to the terminal
using the user name of root and the password of LNXrocks!.
2. At the command prompt, type grep “Inn” sample1 and press Enter. What is displayed
and why?
3. At the command prompt, type grep -v “Inn” sample1 and press Enter. What is displayed
and why? How does this compare to the results from Step 2?
4. At the command prompt, type grep “inn” sample1 and press Enter. What is displayed
and why?
5. At the command prompt, type grep -i “inn” sample1 and press Enter. What is displayed
and why? How does this compare to the results from Steps 2 and 4?
6. At the command prompt, type grep “I” sample1 and press Enter. What is displayed
and why?
7. At the command prompt, type grep “ I ” sample1 and press Enter. What is
displayed and why? How does it differ from the results from Step 6 and why?
8. At the command prompt, type grep “t.e” sample1 and press Enter. What is displayed
and why?
9. At the command prompt, type grep “w…e” sample1 and press Enter. What is
displayed and why?
10. At the command prompt, type grep “ ^I” sample1 and press Enter. What is displayed
and why?
11. At the command prompt, type grep “^I” sample1 and press Enter. What is displayed
and why? How does this differ from the results in Step 10 and why?
12. At the command prompt, type grep “(we|next)” sample1 and press Enter. Is anything
displayed? Why?
13. At the command prompt, type egrep “(we|next)” sample1 and press Enter. What
is displayed and why?
14. At the command prompt, type grep “Inn$” sample1 and press Enter. What is
displayed and why?
15. At the command prompt, type grep “?$” sample1 and press Enter. What is displayed
and why? Does the ? metacharacter have special meaning here? Why?
16. At the command prompt, type grep “^$” sample1 and press Enter. Is anything displayed?
(Hint: Be certain to look closely!) Can you ex plain the output?

Answer 1

Answer: hey! I have given here solutions for 3-7 as you mentioned in the question. Matching pattern may be different but the concept is same. You can understand . thanks

3- grep –v- this command ignores the matching pattern and gives the result that doesn’t match with pattern. You can see the below image.

grep –v “uNix” sample1.txt

It gives the result that doesn’t match this pattern (uNix).

If we give command of step 2 result is- it will match the pattern exactly where it will find that pattern it will print that lines. While in step 3 it is giving the result that does not match the pattern. It is the main difference step 2 and step 3.

4- grep “unix” sample1.txt

This command will match this pattern in a file and display that whole line. Because grep command is used to search files for a particular pattern of characters and display all lines that contain that pattern. This is the main syntax to search a pattern that’s why it will search pattern and display all lines related to it.

5- The –i option enables to search for a string case-insensitively in the given file. It matches the words not case. Suppose we are searching for “inn” word, in this case, it will display all lines which contain “inn” word, does not matter whether the first letter capital or small.

    Step 2- but In step 2 we were searching for “Inn” word in a file. It displayed line only which contain   “Inn” word exactly the same. The first letter should be capital.

            Step 3- option was –v (grep –v “Inn”) by this command, it displayed all lines which don’t contain this pattern(Inn) or if contain “inn” it will display. Because it ignores the matching pattern.

All three steps displayed different results.

6-  grep “I” sample1.txt . This command will display all lines which contain the letter “I” no matter whether is it capital or small. Only letter should be there. Because this grep command to search a pattern in the file. Here it will search for a character in a file.

7- grep “ I “ sample1.txt. This command will display nothing. Because the pattern does not match in file. grep command searches the pattern which enclosed in parenthesis here 2 space is in a pattern. But this pattern does not contain the file’s line. After space, this considers a new string is there. That’s why this pattern does not match. If you will give this pattern “ “ only space it will display all lines which have space. Because the pattern is matched.

In step 6 we were given a pattern that it is matching in files and displayed all lines that contain that pattern. Step 7 pattern does not match in a file that’s why it is not giving any result.

[root@localhost ~]# cat sample1.txt unix is great os.unix is opensource.unix is free os. learn operatinf system.Unix linux which one you choose.uNix is easy t Learn unix.unix is powerful. [root@localhost ~]# [root@localhost ]# [root@localhost ]# grep - v "uNix" sample1.txt unix is great os.unix is opensource.unix is free os. Learn unix.unix is powerful. [root@localhostJ#

[root@localhost # cat sample1.txt unix is great os.unix is opensource.unix is free os. learn operatinf system.Unix linux which one you choose.uNix is easy Learn unix.unix is powerful. [root@localhost ]# [root@localhost ]# [root@localhost j# grep "Unix" sample1 . txt learn operatinf system.Unix linux which one you choose.uNix is easy to learn. [root@localhostj#I to learn.

[root@localhost ~]# cat sample1.txt unix is great os.unix is opensource.unix is free os. learn operatinf system.Unix linux which one you choose.uNix is easy to learn. Learn unix.unix is powerful.[root@localhost]# [root@localhost ]# [root@localhost ~]# [root@localhost ~# grep -i "Unix" sample1.txt unix is great os.unix is opensource.unix is free os. learn operatinf system.Unix linux which one you choose.uNix is easy to learn. Learn unix.unix is powerful. [root@localhost # CS canned with CamScanner

[root@localhost ]# cat sample1.txt unix is great os.unix is opensource.unix is free os. learn operatinf system.Unix linux which one you choose.uNix is easy to learn. Learn unix.unix is powerful. [root@localhost ~]# [root@localhost ]# [root@localhost ]# [root@localhost ~]# grep "u" sample1.txt unix is great os.unix is opensource.unix is free os. learn operatinf system.Unix linux which one you choose.uNix is easy to learn. Learn unix.unix is powerful. [root@localhost ]# CS Scanned with CamScanner

al Email from G [root@localhost ~]# cat sample1.txt unix is great os.unix is opensource.unixis free os. learn operatinf system. Unix linux which one you choose.uNix is easy to learn. Learn unix.unix is powerful. [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# grep "u" sample1.txt unix is great os.unix is opensource.unix is free os. learn operatinf system.Unix linux which one you choose.uNix is easy to learn. Learn unix.unix is powerful. [root@localhost ~]# [root@localhost ~]# [root@localhost ~]# grep [root@localhost ]# sample1.txt e