Top 25 Unix Grep/Sed interview Questions and Answers 2021

1.   Display all lines between 20 and 30 of file x1.

$ Tail +25 x1 | tail -5

2.   To display first 6 lines from file x1.

$ Head -6 x1

3.  Display lines beginning either with alphabet or digit from file x1.

  $ grep "^[aeiou]*[0-9]" x1

 

4.   Display lines that do not contain "unix".

Grep “^[^unix]” filename

5.   Display lines which are not starting with 2 at beginning.

grep ‘^[^2]’ filename

6.   Write a command to display all file name containing only digits in filename.

ls | grep -e "^[0-9$]"

 

8.   To display those lines in between 25 and 50 having pattern 'unix' in it.

   sed -n 25,50p caroline | grep -n "unix"

 

9.   Display lines before a line that contain pattern 'xyz' in file f1.txt.

Grep ‘^xyz’ f1.txt

10.   Find out the number of the character '?' occur in file f1.txt.

Grep -c ‘?’ f1.txt

11. To count the number of words in line 40 through 60 of file f1.txt.

sed -n 40,60p caroline | wc -w

 

12.  Display lines having exactly 50 characters in file f1.

Sed -n 50p f1

13.   count the number of blank lines in file f1.

Grep -c “ “ f1

14.  count the number of blank lines in between 10 and 20 of x1.

grep -c "^$" caroline

 

15.  display lines having at least one * character in file x1.

Grep ‘.’ X1

16.  Display the directory listing.

ls -d */

 

17.  Display files having read and write permission for the group.

Chmod 624 filename

18.    Write a command to substitute doshi with desai.

Sed -e ‘s/doshi/desai/g’ filname

19. To display all lines that contain pattern bc* in a line.

grep “bc*” filname

20.  To replace tybca with TYBCA in input file in.sh and write those lines to output file out.sh.

    Sed -n ‘s/tybca/TYBCA/p’ in.sh>out.sh

21.   To display occurrences of 'BCA' in file x1.

Grep “BCA” x1

22. To replace all occurrences of 'she' with 'he' and 'hi' with 'hello'.

  sed -i ‘s/she/he/g’ filename |   sed -i ‘s/hi/hello/g ’ filename

 

23.  To print lines with line nos. which contain "marketing".

      grep -n ‘marketing’ file name

24.      Display lines which starts with 'The'.

       Grep ‘^the’ filename

25.  Delete all vowels from file x1. 

sed  's/[aeiou]//g' caroline