Here is the list of top and best difficult unix interview questions for experienced and freshers asked in real time. I wil share unix shell scripting interview questions and answers for experienced, unix interview questions for testers, unix interview questions for experienced support, unix interview questions for informatica, basic unix commands with examples shortly.
1. What does the command “$ls | wc –l > file1” do?
2. What is the significance of the “tee” command?
3. What does the command “$who | sort –logfile > newfile” do?
4. What is the difference between cat and more command?
5. Write a command to kill the last background job?
6. What will the following command do?
7. How to do redirection in UNIX ?
8. How is the command “$cat file2 “ different from “$cat >file2 and >> redirection operators ?
9. Explain the steps that a shell follows while processing a command.
10. What difference between cmp and diff commands?
11. Which command is used to delete all files in the current directory and all its sub-directories?
12. What is the use of ‘grep’ command?
13. What is the use of the command “ls -x chapter[1-5]”
14. Write a command to display a file’s contents in various formats?
15. How to create a new file system in UNIX ?
16. Is it possible to restrict incoming message?
17. What is the use of ‘du’ command ?
18. How to count number char, line in a file ?
19. Name the data structure used to maintain file identification?
20. How many prompts are available in a UNIX system?
21. How does the kernel differentiate device files and ordinary files?
22. How to switch to a super user status to gain privileges?
23. What are shell variables?
24. How to terminate a process which is running and the specialty on command kill 0?
25. Explain kill() and its possible return values.