Lab 6: Arithmetic and Find

Questions

1. Write a script which prints a triangle of * characters. The first row should be a single *, the second **, and so on. You can use echo -n to print output without a newline at the end. The number of rows is specified by the command line argument -r. If no argument is provided, print 4 rows.

   > ./triangle.sh -r 1
   *
   
   > ./triangle.sh
   *
   **
   ***
   ****
   
   > ./triangle.sh -r 6
   *
   **
   ***
   ****
   *****
   ******
   

2. Modify your triangle script so that instead of printing *s, it prints a character selected using the rules below:
   • If you are printing the last column, print \
   • Otherwise, if you are printing the first column, print |
   • Otherwise, if the row number is odd, print L
   • Otherwise, print *

   > ./triangle.sh -r 1
   \
   
   > ./triangle.sh
   \
   |\
   |L\
   |**\
   
   > ./triangle.sh -r 6
   \
   |\
   |L\
   |**\
   |LLL\
   |****\
   

3. Find the file called kangaroo.cow. Hint: start in /usr
4. Fine the directory called mess under /lab
5. Scattered across the subdirectories of mess are 5 scripts with the word lab in their name. Write a find command to make these scripts executable and move them to /lab/week6/safe. Remember that wildcards in find patterns must be quoted, otherwise shell will expand them.

Bonus

1. Modify triangle.sh to support command-line arguments for additional functionality:

   --bottom -b Print a line of dashes (-) beneath the triangle to form a bottom edge
   
   --rows, -r=ROWS Number of rows to print (default 4)
   
   --character, -c=CHAR Use CHAR in place of * when printing. You may assume CHAR is a single-character string
   
   --help, -h Display this help message and exit
   

Department of Computer Science & Software Engineering The University of Western Australia Last modified: 8 February 2022 Modified By: Daniel Smith