Test #4A Shell Programming

Shell Programming - Points: 70  (11 of 35%)

[TEST PART II - CLOSED BOOK - NO COMPUTER] Write code for an executable
shell script that will do the following actions, in the exact order given
below.  You will write approximately 40-45 lines of executable code.  For
full marks, you must put a one-line comment containing the step number in
front of the executable code in each step.  Do not put a Step Number
comment as the first line of the script!

Summary and Purpose (what this script will do):
     The script expects a single optional C++ program source file name on
     the command line.  If the file argument is missing, get the file name
     from the user.  It will compare the number of lines in this source
     file with the number of lines in another file, and it will compile
     whichever program has more lines.  It backs up the output file first.
                   ________________________________________

  1.   [Points: 5] Structure your script to include these standard DAT2330
       script sections: interpreter, one-line description, syntax, search
       path, and file creation mask.  Do not include the Purpose or
       Assignment Label sections.

  2.   [Points: 7] Issue a good error message (follow the DAT2330
       guidelines) and exit the script with status 1 if there is more than
       one command line argument.

  3.   [Points: 7] If there is a command line argument, put it into a
       variable named prog; otherwise, the script must get the C++ program
       source file name from the user and put it into the same named
       variable.  Quick-exit the script with status 2 if the user signals
       EOF to the script.  (No error message is needed.)

  4.   [Points: 6] Make sure the pathname in variable prog is not an empty
       string; otherwise, issue a good error message and exit the script
       with status 3.

  5.   [Points: 7] Make sure the pathname in variable prog is a plain
       file; otherwise, issue a good error message and exit the script
       with status 4.

  6.   [Points: 7] Make sure the file whose name is in variable prog is
       not an empty file (has a size larger than zero); otherwise, issue a
       good error message and exit the script with status 5.

  7.   [Points: 6] If the file whose name is in variable prog is not
       readable, add read permissions for user and group (not for others).
       Quick-exit the script with status 6 if changing permissions fails.
       (No output or error messages are needed.)

  8.   [Points: 4] Put only the count of lines in the file named by the
       prog variable into a variable named plines. Quick-exit the script
       with status 7 if the counting fails.

  9.   [Points: 4] Put only the count of lines in the file named foo.cpp
       into a variable named flines. (You may assume this file exists; no
       code is needed.)  Quick-exit the script with status 8 if the

       counting fails.

  10.  [Points: 4] If something with the name of happy already exists in
       the current directory, rename it to be happy.bak.

  11.  [Points: 8] Compile whichever of the two C++ source files that has
       the most lines into an output file named happy. Quick-exit the
       script with status 9 if the compile fails.

  12.  [Points: 5] If there is a readable Makefile in the current
       directory, and if the Makefile contains the name of the larger of
       the two C++ source files, print a message on standard output
       telling the user to use the make program to compile the file next
       time.  The message must contain the name of the source file.  No
       other output should appear in this step.

Put a one-line comment containing the step number on the line above the
executable code in each step.