Shell Programming and Scripting

General Considerations

1)  Think about the structure of your program before you write any code.

2)  Write your program in small parts.  Test each part before you add the next.

3)  Write your source code in plain ASCII (especially not RTF or DOC).

4)  Include comments with:
      name, assignment, and date (at the top)
      a description of what your program does and how to use it (at the top)
      the logic of your program (if needed, distributed throughout)

5)  Use descriptive names for your variables, functions, etc.

6)  Prompt for interactive input (if applicable).

7)  Test your program with different inputs.


Write a bash program to:

a)  Input zero or more integers from standard input (one per line)

b)  Input zero or more integers from command line arguments

c)  Output the sum of all input numbers on standard output


It is not necessary to check for invalid input or to format the output.

Due midnight 30 November.

# A small script that can add 5 numbers from the script arguments
# and 5 numbers that can be entered as a user input.

# Usage: Run the program and if no arguments you will be prompted to enter
# 5 numbers from standard input otherwise you can add the 5 arguments and
# then you will be prompted to enter 5 more numbers.

# When there are no arguments the user can enter the numbers
# from standard input and then the addition will be done.
if [ $# -lt 1 ]
then
echo Please enter you numbers \:
read num1
read num2
read num3
read num4
read num5
sum=$(( $num1 + $num2 + $num3 + $num4 + $num5 ))
echo The total is $sum

# When the user enters the numbers as arguments to the script he will
# be prompted to enter numbers as standard input as well and have the
# the addition done.
elif [ $# -le 5 ]
then
read num1
read num2
read num3
read num4
read num5
sum=$(( $num1 + $num2 + $num3 + $num4 + $num5 ))
echo The grand total is $(( $sum + $1 + $2 + $3 + $4 + $5 ))
fi