Unix Interview Question and Answers

1. What is a shell?
  A Unix shell is the program which reads user input from the command line and executes actions based upon that input.
2. Define session?
  • A session is a collection of one or more process groups.
  • A process establishes a new session by calling setsid function. This function returns process group id if OK.
3. What do you mean by signal?
  • Signals are software interrupts.
  • Signals provide a way of handling asynchronous events: a user at a terminal typing the interrupt key to stop a program or the next program in the pipeline terminating prematurely.
4. What is unix?
  • UNIX is the most popular operating system on multi-user systems.
  • This operating system originated as a single-user system. It started off on a cast-off DEC PDP-7 at Bell laboratories in 1969.
  • Ken Thompson, with ideas and help from Dennis Ritchie, and others, wrote a small, general-purpose operating system.
5. Define message queue?
  • Message queue is a linked list of messages.
  • It is used to make a communication between the related or unrelated processes.

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