Here is a listing of Linux / Unix Technical Interview Questions & Answers for experienced IT professionals as well as fresh engineering graduates. These questions can be attempted by anyone focusing on Linux Development and Systems programming.
1. What is a context switch?
a) Kernel switches from executing one process to another
b) Process switches from kernel mode to user mode
c) Process switches from user mode to kernel mode
d) None of the mentioned
Answer: a
2. Pid of init process
a) 0
b) 1
c) 32767
d) none of the mentioned
Answer: b
3. What is the default maximum number of processes that can exist in Linux?
a) 32768
b) 1024
c) 4096
d) unlimited
Answer: a
4. How do you get parent process identification number?
a) waitpid
b) getpid()
c) getppid()
d) parentid()
Answer: c
5. Parent process id of a deamon process is_________________.
a) 2
b) 3
c) 4
d) 1
Answer: d
6. The process which terminates before the parent process exits becomes
a) Zombie
b) Orphan
c) Child
d) None of the mentioned
Answer: a
7. Return value of fork() system call can be:
a) -1,<0, 0
b) -1,>0, 0
c) -1,<0
d) none of the mentioned
Answer: b
8. If the fork() system call returns -1, then it means?
a) No new child process is created
b) The child process is an orphan
c) The child process is in Zombie
d) none of the mentioned
Answer: a
9. Fork returns _____ to parent process on success
a) 0
b) child process id
c) parent process id
d) none
Answer: b
10. How many times printf() will be executed in the below mentioned program?
main()
{
int i;
for (i = 0; i < 4; i++)
fork();
printf("my pid = %dn", getpid());
}
a) 4
b) 8
c) 16
d) 32
Answer: c
11. What is the output of the below code?
void exit_handler1();
void exit_handler2();
int main()
{
int pid;
atexit(exit_handler1);
atexit(exit_handler2);
pid = fork();
if(pid == 0)
{
_exit(0);
}
else
{
sleep(2);
exit(0);
}
return 0;
}
a) Only child executes the exit_handler 1 and 2
b) Only parent executes the exit_handler 1 and 2
c) Both parent and child executes the exit_handler 1 and 2
d) Neither parent nor child executes the exit_handler 1 and 2
Answer: b
12. What is output of the following program?
int main()
{
fork();
fork();
fork();
if (wait(0) == -1)
printf("leaf childn");
}
a) “leaf child” will be printed 1 times
b) “leaf child” will be printed 3 times
c) “leaf child” will be printed 4 times
d) “leaf child” will be printed 8 times
Answer: c
13. Which niceness value among the following indicate most favorable scheduling?
a) 0
b) 19
c) 5
d) -20
View Answer
Answer: d
14. The maximum time slice that can be given to a process in Linux (where tick is 10ms) is
a) 150ms
b) 10ms
c) 300 ms
d) 600ms
Answer: d
15. Nice can be used by an ordinary process to
a) increase the priority of a process
b) decrease the priority of a process
c) increase or decrease the priority of a process
d) none of the mentioned
Answer: b