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. If a signal is received by a process, when will it be processed?
a) It is processed immediately
b) It is processed when process is switching to kernel mode
c) It is processsed in the next timeslice given to the process
d) None of the mentioned
Answer: b
Clarification: None.
2. Which signal is generated when we press control-C?
a) SIGINT
b) SIGTERM
c) SIGKILL
d) SIGSEGV
Answer: a
Clarification: None.
3. Which signal is generated when we press ctrl-Z?
a) SIGKILL
b) SIGSTOP
c) SIGABRT
d) SIGINT
Answer: b
Clarification: None.
4. Which signal is sent when the Child process terminates?
a) SIGINIT
b) SIGKILL
c) SIGSTOP
d) SIGCHLD
Answer: d
Clarification: None.
5. Which of the following signal cannot be handled or ignored?
a) SIGINT
b) SIGCHLD
c) SIGKILL
d) SIGALRM
Answer: c
Clarification: None.
6. Another signal that cannot be caught is:
a) SIGPIPE
b) SIGHUP
c) SIGSTOP
d) SIGUSR1
Answer: c
Clarification: None.
7. When real interval timer expires which signal is generated?
a) SIGINT
b) SIGCHLD
c) SIGKILL
d) SIGALRM
Answer: d
Clarification: None.
8. Signals are handled using which system call?
a) kill
b) signal
c) both
d) none
Answer: b
Clarification: None.
9. Default action of SIGSEGV is
a) Terminate
b) Core dump + Terminate
c) Stop
d) Cont
Answer: b
Clarification: None.
10. The kill system call is used to
a) Send shutdown messages to all by superuser
b) Send a signal to a process
c) Kill processes
d) Stop the processes
Answer: b
Clarification: None.
11. What is the output of the below code?
void sig_handler ( int signum) { printf(“Handled the signaln”); } int main() { int pid; signal (SIGKILL, sig_handler); pid = fork(); if (pid==0) { kill(getppid(), SIGKILL); exit(0); } else { sleep(20); } return 0; }
a) Error child cannot send a SIGKILL signal to parent
b) Parent goes to the signal handler, prints handled the signal and goes back to sleep
c) Parent goes to the signal handler, prints handled the signal and exits
d) Parent exits without going to the signal handler
Answer: d
Clarification: None.