This function is only defined later. Move the definition up.

Problematic code:

#!/bin/sh
myfunction

myfunction() {
  echo "Hello World"
}

Correct code:

#!/bin/sh
myfunction() {
  echo "Hello World"
}
myfunction

Rationale:

You are calling a function that you are defining later in the file. The function definition must come first.

Function definitions are much like variable assignments, and define a name at the point the definition is "executed". This is why they must happen before their first use.

This is especially apparent when defining functions conditionally:

case "$(uname -s)" in
  Linux) hi() { echo "Hello from Linux"; } ;;
  Darwin) hi() { echo "Hello from macOS"; } ;;
  *) hi() { echo "Hello from something else"; } ;;
esac

hi

Exceptions:

None.