Question

Related to SO.

fizzy.sh:

#!/usr/bin/env sh

div3() {
    expr $1 % 3 = 0
}

div5() {
    expr $1 % 5 = 0
}

fizzy() {
    if [ $(div3 $1) ] && [ $(div5 $1) ]; then
        expr "FizzBuzz"
    elif [ $(div3 $1) ]; then
        expr "Fizz"
    elif [ $(div5 $1) ]; then
        expr "Buzz"
    else
        expr "$1"
    fi
}

echo $(fizzy 1)
echo $(fizzy 2)
echo $(fizzy 3)

Example:

$ ./fizzy.sh
FizzBuzz
FizzBuzz
FizzBuzz

Answer 1

expr $1 % 3 = 0 yields 1 or 0, depending on whether the result of $1 % 3 is zero or not, but if treats 0 as true, not false.

sh-3.2$ if [ 0 ]; then echo ok; fi
ok

So you’d need to compare the output of your function against 1. Something like this:

#!/usr/bin/env sh

div3() {
    expr $1 % 3 = 0
}

div5() {
    expr $1 % 5 = 0
}

fizzy() {
    if [ $(div3 $1) -eq 1 ] && [ $(div5 $1) -eq 1 ]; then
        expr "FizzBuzz"
    elif [ $(div3 $1) -eq 1 ]; then
        expr "Fizz"
    elif [ $(div5 $1) -eq 1 ]; then
        expr "Buzz"
    else
        expr "$1"
    fi
}

for (( i = 1; i <= 15; i++ ))
do
    echo $(fizzy $i)
done