1. Modify your solution to Exercise 12.6 to send the formatted
   output to the file "Ex12_06.out".

2. Read Exercise 12.7. Partial solution ex12_7.pl is available
   on today's page. Complete the format declaration in the 
   solution program to produce the required table.

3. Skim the manual page for the information about the "last" command 
   %man last

   Next, run the last command on your system and examine the output 
   (type Ctrl-C when done):
   %last | more

   You can attach the output of a command to a file handle as shown in 
   process_last.pl. After that you can use the file handle as usual.
 
   Complete process_last.pl script to do the following (use formats):
   A. For each day in the log, report how often each user logged in.
   B. For every user in the log, report the number of logins and 
      and the average time on the system.
   C. Report how often user "root" logged in.
   D. Since your log file is very short, modify the code to
      read last.log file available on course page and produce 
      reports for #A and #B. How many
      report pages did you generate? (The purpose of this question is 
      to make sure you know how to use $% variable).
   E. Report the dates and times of the system reboot (Examine the
      last few lines of last.log to determine the format. You can
      use the following command to do so:
      %tail last.log 

   Note: 6+22:35 in the last column means the user was logged in for
         6 days, 22 hours and 35 minutes.
       
         If the last field is "still logged in" compute the total
         duration on the system based on the day of login and time and the
         current day and time. 
    
4. Write a program to rotate log files. Rotate apache's error.log
   over a period of 1 week. Here are more details: 
      Assume, that you run the script today and the current directory
   contains only error.log file. Copy error.log file into error.log.0 file
   and exit the script.   
      Assume, that you run the script today and the current directory
    contains error.log and error.log.0. Now, your script should copy
    error.log.0 into error.log.1 and error.log into error.log.0.
   ....
      Assume, that you run the script and the current directory contains
    error.log, error.log.0, error.log.1, error.log.2, errror.log.3, 
    error.log.4, error.log.5, and error.log.6. Your script should
    delete error.log.6, copy error.log.5 into error.log.6, copy
    error.log.4 into error.log.5, ....., copy error.log into error.log.0.

5. Download error.log file from the course web page into your
   current working directory. Run your solution to Exercise 12.8
   using error.log file. Does your program produce the output
   exactly as shown on p. 398? Examine error.log to find why
   the output differs (compare to the sample line from the error
   log on p. 386). Modify your code to produce the exact output.
   [If you didn't write the program, Deitel's solution is available
   in ex12_8.pl file].

6.  Modify rotation script from Problem # 4 as follows:

    A. Intermediate level: modify this script to perform rotation at a 
    certain time of the day only (You can use localtime to find the
    current time, sys admins would do it in a cron script,
    though). For example, only do the rotation if the script is executed
    between midnight and 1:00am. Otherwise, do nothing.

    B. Advanced level: modify this script to do the rotation of the
    real Apache error.log. The script should be executed by user "root"
    only if root provided correct password. Hint: use getpwuid()
    and crypt functions.