Demonstration of Bash input values, assignment, and null checking with an "echo name" example.

echo-name.sh

#!bin/bash

set -o pipefail

# Assign first value to a named global variable
NAME="${1}"
# Exit with an error if not set
if [[ -z $NAME ]]; then echo "You need to call this with a value!" && exit 1; fi

# Echo first value coming into function
function echoName() {
  echo "Hello there, $1!"
}

echoName $NAME