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Basic shell scripting interview questions


1. How do you find out the current directory you are in?
        pwd

2. How do you find out what's your shell?
        echo $SHELL

3. How do you list currently running process?
        ps

4. How do you stop a process?
        kill pid

5. How do you stop all the processes, except the shell window?
        kill 0

6. What's the command to find out users on the system?
        who

7. How do you count words, lines and characters in a file?
        wc filename

8. What's the command to find out today's date?
        date

9. How do you find out your own username?
        whoami

10. How do you remove a file?
        rm filename

11. How do you search for a string inside a given file?
        grep string filename

12. How do you search for a string inside a directory?
        grep string *

13. How do you search for a string in a directory with the subdirectories recursed?
        grep -r string *

14. What's the conditional statement in shell scripting?
        if {condition} then  fi

15. How do you do number comparison in shell scripts?
        -eq, -ne, -lt, -le, -gt, -ge

16. How do you fire a process in the background?
        ./process-name &

17. How do you refer to the arguments passed to a shell script?
        $1, $2 and so on. $0 is your script name.

18. How do you find out the number of arguments passed to the shell script?
        $#

19. How do you capture the return code?
        $?

20. How do you know about running processes of a particular user?
        ps -u username