linux FAQ(zz)

1.Which is the command used to find the available shells in your Operating System Linux ?

Ans : $echo $shell

2.Which is the command used to view the environment variables?

Ans: printenv

3. How do you recall last command from the history list in Cshell ?

Ans: !!

4. How do you print the current job in Cshell ?

Ans: %%

5. Which is the command used to find the no of bytes in the file shell ?

Ans: du file name

6. Which is the command used to edits the input stream, line by line?

Ans: sed

7. What is the difference between finger and who?

Ans: Finger was a way to get information about a user from another system Who is used to find who all are using current machine.

8. Which are the Protocols used to access remote machines?

Ans: SSH ,RSH ,FTP

9. Which is the basic command while transfer a file from your home to the other user?

Ans: FTP

10. Which is command used to create a file Linus of zero bytes?

Ans: touch

11. Which is the command used to select parts of a line?

Ans: cut filename

12. How do you Find the free space of the hard disk in your home?

Ans: df filename

13. f a file A contains 200 bytes of data and file B contains 150 bytes of data, How do you say A is 50 bytes more than B?

Ans: cmp file A file B

14. Which is the command used to find the number of files in directory?

Ans: ls | wc -l

15. How will you change your shell?

Ans: tcsh

16. How will you change file permissions?

Ans: using chmod

17. Difference between find and locate?

Ans: Locate uses an internal database to look up indexed files. This database need to be updated using a command “updatedb”.
Find does only a normal search.

18. How will you search for a pattern (String) in a file?

Ans: grep “string” filename

19. How will you kill a process? Give one example?

Ans: 1. ps = It will list all processes on that shells

           2. kill process ID

20. How will you remove a file interactively?

Ans: rm -i filename

21. Can we remove a nonempty directory? If yes how?

Ans: rm -rf dirname

22. What do you mean by “su”? What is the difference between “su” and “su -“?

Ans:su means switch user it changes the shell we to key a exit to come back to previous shell.

23. How will you delete 50 lines in vi?

Ans:50 dd in escape mode.

24. How will you search for a pattern in vi?

Ans: ?pattern

25. How will you perform cut and paste in vi?

Ans: dd for cut p for paste

26. How to list out the files in a directory according to there size?

Ans: ls -S

27. How to insert a word as firstword for all lines in the text?

Ans : sed -i s/word/firstword/

28. Which of the following characters is used to signify the beginning of a line?
A. %     B. $     C. ^     D. ~

Ans : C

29. If you want to find every line in a file that contains a number. Which of the following regular expressions will accomplish this?
A. -n     B. "0 1 2 3 4 5 6 7 8 9"     C. [0-9]     D. [^0-9]

Ans : C

30.If you want to find all matches for two distinctly different values. Which character is used to signify that you want to match two values?
A. back slash (\)     B. forward slash (/)     C. pipe (|)     D. ampersand (&)

Ans : C

31. Which of the following should be used to find "Sam" and "Samantha" in a file?
A. Sam(antha)*     B. Sam[antaha]     C. Sam|antha     D. Sam\(antha\)\?

Ans : B

32. Which of the following characters is used to signify the end of a line?
A. %     B. $     C. ^     D. ~

Ans : B

33. What set of characters will be matched if the expression is [1-9A-D]?
A. 123456789ABCDabcd     B. 123456789ABCD     C. 19ADad     D. 19AD

Ans : B

34. Which of the following regular expressions should be used to find lines that do not contain numbers?
A. -n     B. "\0 \1 \2 \3 \4 \5 \6 \7 \8 \9"     C. [0-9]     D. [^0-9]

Ans : D

35. Which of the following can be checked to see how many positional parameters were used to call a script?
A. $#     B. $$     C. $!     D. $?

Ans : D

36. Which switch should be used with grep to print all lines in a file that do not match the search criteria given?
A. -i     B. -v     C. -c     D. -n

Ans : B

37. Which of the following would be the result of the command echo 1{2,3,4}5 (choose all that apply)?
A. 15     B. 125 135 145     C. 12345     D.1{2,3,4}5

Ans : B

38. Which switch should be used with grep to ignore case as you look for matches in a file?
A. -i     B. -v     C. -c     D. -n

Ans : A

39. Which switch should be used with grep to count all lines in a file that match the search criteria?
A. -i     B. -v     C. -c     D. -n

Ans : C

40. Which of the following utilities processes most quickly?
A. grep B. egrep C. fgrep

Ans : The fgrep utility does not have the same regular expression set as the other two, and is thus able to execute the fastest hence ans is C.

41. Which of the following regular expressions can be used to find all blank lines in a file?
A.""     B. ^$     C. ^" "$     D. [ ]

Ans : B

42. If the value of ALT is set to the string "MPC", what will the command echo '$ALT' return?
A. $MPC     B. MPC     C. ALT     D. $ALT

Ans : D

43. Which is the command used to create chain of directories?

Ans : mkdir -p dir1/dir2/dir3

44. Which is the command used to see two files at a time?

Ans : vim -o filename1 filename2

45. What is the usage of top command?

Ans : It will list all the currently running processes on CPU.

46. How we can use a sed command as a head command?

Ans : sed “5q” filename

47. What is the result of “%s/Kacper/Kacpertech/g “?

Ans : Kacper will get replaced my another string Kacpertech in all the lines of the file.

48. Which of the following interprets your actions when typing at the command line for the operating system?
a. Utility     b. Application     c. Shell     d. Command

Ans : C

49. Write a syntax for foreach loop in shell script?

Ans : foreach variable name (some list)
command1
command2
.........
end

50. How we can set the date and time for the files?

Ans : using touch operator