Checking a bash script's requirements are met by the host OS

check-required-utilities.sh

# required utilities
required=(
	grep
	awk
	curl
	jq
)

missing=()

for utility in "${required[@]}"
do
	if ! type "${utility}" >/dev/null 2>&1
	then
		missing+=("${utility}")
	fi
done

if ((${#missing[@]}))
then
	cat <<-EOM
		This script requires the following utilities, which could not be found.  Please install them and try again:
    
		$(IFS=$'\n'; echo "${missing[*]}")
    
	EOM
	exit 1
fi