BCS 215 Final Exam

In your home (login) directory, create a subdirectory named "shared".
Set permissions allowing new files to be created by anyone in the group "/home/students/" BUT not allowing directory to be searched.
Users outside the group can access a file if (and only if) they know the file name.

Create the following files in this (~/shared/) directory:
• A hidden file with a name that ends with the last two digits of your RAM ID number.
• Write the full path name of the hidden file in a new (non-hidden) file whose name is your first name, beginning with a Capital letter.    
• Create a file named "run" that anyone can execute, but only group members can read, and nobody but you can write.
• Create a file named "frozen" that anyone can execute, but nobody can read or write.
• Create a file named "public" that anybody can read/write, but only you can execute.
• Create a file named "secret" that anyone can execute, but only you can read or write.
• Create a file named "top" that only you can read (and nobody can write or execute).

Everything below should be in your ~/final/ directory ("~/final/"), along with your projects three, four, five.

1. Your First and Last name.
2. Today's date and time.
3. What day of the year (from 1 to 365) is today?
4. How many user names (in "/home/students/") begin with same first letter as yours?

   Make a link to the "presidents/" file in my "final/" directory (or to link in my "bam/" directory), and use it for the next 5 items.

5. In the "presidents/" file, how many lines do NOT contain the string "None"?
6. How many lines do NOT contain either "John" OR "William"
7. The 5th field contains a range of years separated with a dash, such as "(1861-1865), OR a single year, such as "(1841)".   How many lines have NO dash in this field.
8. The 9th field also contains either a range of years or a single year. Count how many lines do NOT have a dash in this field.

In your ~/final/ directory, write a bash script named   seven   that asks the user to enter a list of positive numbers, one per line, with a zero at the end of the list.

As each positive value is read in, do the following:
1. * Output the value, add it to total "t", and add one to counter "n".
2. $ Update variables "hi" & "lo" to contain biggest & smallest values read in, so far.
   (HINT: Initialize both of these to the first value read in, before starting input loop.)
3. $ Square each input number (i.e. multiply it by itself), and add that to a quantity called "ss" (for the sum of the squares).

   SUGGESTION:   Do starred (*) items first; add "$" items later.

When the zero is read in, do the following:
4. * Be sure NOT to increase the counter!
5. * Divide total (t) by counter (n), to compute average.
   (HINT: Don't worry about losing any fractions when these two integers are divided.)
6. $ Set "tt" equal to the square of the total "t" (by multiplying t by itself).
7. $ Set "diff" equal to ss - tt/n
8. $ Compute the variance v = (ss - tt/n) / n   ( = diff / n )
9. * Output the following (with approriate text to identfy each result):
   • * The total (t).
   • * The number of input values (n).
   • * The mean average of the values.
   • * The range of values (smallest to biggest).
   • $ Sum of the squares (ss), tt/n, and diff.
   • $ Variance (v)

   Test your script, with output to console, and input from keyboard; then run it with input from data files in ~martinb/final/ and output to files in your ~/final/ dir.
   

   Enter a list of positive values (ending the list with zero). 11 12 13 14 15 16 17 18 19 0 Smallest: 11 Biggest: 19 Total is 135 Count is 9 Average: 15 ------- ss-tt/n= 2085 - 18225 / 9 = 60 variance: 6

   Below are some tests you can perform:

   • If all values are equal, variance should be zero.
   • If values in list are very different, variance is large.
   • If hi & lo are far apart, variance should be large.
   • If the list contains the numbers 1 thru 10, average should be 5 and variance should be 8.
   • If the list contains "100 200 300" the average should be 200 and the variance should be 666.

   Input from ~martinb/final/data.1;
       and redirect output to your file seven.1.
   Input from ~martinb/final/data.2.
       and redirect output to seven.2.
   Input from ~martinb/final/data.3.
       and redirect output to seven.3.
   Input from ~martinb/final/data.4.
       and redirect output to seven.4.