CS 497C - Quiz 3 Sample Questions
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Part 1: 

(4) 1. How do you redirect the standard error to a file?
       (1) >> (2)  > (3) 1>  (4) 2>
(2) 2. Which command is used to break the output in two streams?
       (1) tar (2) tee (3) tail (4) telnet
(1) 3. Which one is equivalent to cat foo | ispell -l?
       (1) ispell -l < foo (2) ispell -l << foo 
       (3) ispell -l > foo (4) ispell -l >> foo
(1) 4. Which command can you use to translate characters in a character
       stream?
       (1) tr (2) pr (3) tee (4) tar
(2) 5. Which one is used to select only one copy of the repeated lines?
       (1) uniq -u (2) uniq -d (3) uniq -c (4) uniq -i
(2) 6. How do you noninteractively check spelling?
       (1) cat foo | ispell (2) ispell -l < foo (3) ispell foo (4) ispell < foo
(3) 7. Which one will you use to make sure that a process is killed?
       (1) kill -7 (2) kill -8 (3) kill -9 (4) kill -10 
(4) 8. Which command can you use to kill the login shell?
       (1) kill 0 (2) kill $$ (3) kill -1 (4) kill -9 0
(1) 9. Which system variable is used to store the PID of the last 
       background job?
       (1) $! (2) !! (3) $% (4) %!

Part 2: 

   1. Which are three standard files in the UNIX system and what are
      their default source?

Ans: 1) Standard input - The default source is the keyboard.
     2) Standard output - The default destination is the terminal.
     3) Standard error - The default destination is the terminal.
    
    2. What is a filter? Where does a filter get its input from?

Ans: 1) A filter is a command which uses both standard input and standard 
        output.
     2) It can accept input from (i) a file with < (ii) a pipeline using |. 
        Most filters accpet input from the keyboard as well.

   3. Select lines 5 to 10 of a file in two ways by using head and tail. 

Ans: 1) tail +5 foo | head -6
     2) head -10 foo | tail +5

   4. How will you find out the number of times the character ? occurs
      in a file?

Ans: Delete all characters except the ? and then make a character count
     with wc:

     tr -cd '?' < foo | wc -c

   5. What are three distinct phases in the creation of a process?  Explain 
      it.

Ans: 1) Fork - A copy of the process that invokes it is created.
     2) Exec - The parent then overwrites the copy to create the child.
     3) Wait - The parent waits for the death of the child.

   6. What can you do with the job control facilities?

Ans: 1) Put a job to the background (bg).
     2) Bring it back to the foreground (fg).
     3) List the active jobs (jobs).
     4) Suspend a foreground job ([Ctrl-z]).
     5) Kill a job (kill).
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