CS 497C - Mid-Term Exam - Name: ____________
Date: Friday, October 19 (in class)

Part 1: (44 points - 4 points for each problem)

    (2) 1. Which part of the operating system gets loaded into memory as soon 
           as the system is booted?
          (1) shell (2) kernel (3) file (4) process

    (3) 2. What command is generally used to end an input session?
          (1) Ctrl-z (2) Ctrl-q (3) Ctrl-d (4) Ctrl-l

    (2) 3. If the {\bf apropos} command is not available, which command can 
           you use?
          (1) man -l (2) man -k (3) man -f (4) man -c
    (4) 4. How do you delete text from the current line to the beginning of 
           the file in vi?
          (1) 1GdG (2) dG (3) d0G (4) d1G
    (1) 5. How do you globally replace Internet with Web occurring in all 
           lines using vi? 
          (1) :1,\$s/Internet/Web/g  (2) :1,\$s/Internet/Web 
          (3) :.,\$s/Internet/Web/g  (4) :.,\$s/Internet/Web
    (1) 6. How can you quit emacs?
          (1) [Ctrl-x][Ctrl-c] (2) [Ctrl-x][Ctrl-f]
          (3) [Ctrl-x][Ctrl-q] (4) [Ctrl-x][Ctrl-s]
    (3) 7. What command is used to interactively delete files?
          (1) rm (2) rm -d (3) rm -i (4) rm -a
    (3) 8. What command is used to rename a file?
          (1) ren (2) rename (3) mv (4) newname
    (2) 9. How would you display all files including hidden ones in columns
           and identify directories and executables?
          (1) ls -lat (2) ls -Fax (3) ls -tar (4) ls -Rak
    (3) 10. What is equivalent to chmod 711 file?
          (1) chmod u=rw,go=x file  (2) chmod u=rw,go=rx file
          (3) chmod u=rwx,go=x file (4) chmod u=rwx,go=rx file
    (4) 11. How do you symbolically link /usr/games/netris with a file of 
            the same name in your current directory?
          (1) ln . /usr/games/netris    (2) ln /usr/games/netris . 
          (3) ln -s . /usr/games/netris (4) ln -s /usr/games/netris . 

Part 2: (56 points)

   1. What is an operating system? List three different operating systems.
      (6 points)

Ans: (1) An operating system (sometimes abbreviated as "OS") is a program
         that functions as  a virtual machine (layer of software on top of 
         bare hardware) and a resource manager (software that controls 
         access to computer).
     (2) DOS, Windows, Mac OS, and UNIX.

   2. What is PATH? How do you evaluate its value?  (6 points)

Ans: (1) PATH is a system variable which stores a lists of directories
         that the shell searches to locate a command.
     (2) Use echo $PATH to evaluate its value.

   3. Name three ways of quitting vi and saving the file.  (6 points)

Ans: Use the command :x, :wq, or ZZ to save and quit the vi editor.

   4. How do you mark a region, copy it, and put it in the new location
      in emacs?  (5 points)

Ans: Mark the beginning of the region by [Ctrl-Spacebar] or [Ctrl-@] and 
     move the cursor to the end of the region. Copy it by [Alt-w]. Put it 
     by [Ctrl-y].

   5. How does UNIX divide files into three categories?  (6 points)

Ans: Ordinary file - Also known as regular file. It contains only data as 
                     a stream of characters.
     Directory file - A folder containing the names of other files and 
                      directories.
     Device file - It represents all hardware devices.

   6. What directories do . (a single dot) and .. (two dots) represent
      respectively? (4 points)

Ans: . (a single dot) represents the current directory.
     .. (two dots) represents the parent directory.

   7. If mkdir foo doesn't create the directory, what could be the possible 
      reasons? Write at least three possible reasons.  (6 points)

Ans: (1) The directory foo already exists.
     (2) An ordinary file with the same name exists.
     (3) The user doesn't have permission to create it.

   8. A file with {\tt -rwxr-x--x} has what permissions assigned to it?
      (6 points)

Ans: Owner: read, write, execute;
     Group: read, execute;
     Others: execute.

   9. Specify which file attributes change when you copy a file from another 
      user account.  (6 points)

Ans: (1) The file's owner changes to the user who copys this file.
     (2) Last modification and access time changes to the time of copy.
     (3) If the two users are in different groups, the file's group
         changes.
     (4) File permissions change to the default permission of the user
         who copy this file.

  10. Use the {\tt find} command to move all files with the html extension
      (i.e. {\tt *.html}) from the current directory to the htdocs directory 
      under the parent directory.
      hint: This can be done with the -exec operator, followed by the command 
      to be executed and terminated with the sequence {} \; (5 points)

Ans: find . -name "*.html" -exec mv {} ../htdocs \;