Looks for "named arguments" in an array, which take the form key=value

get_named_arg.sh

# Searches for a named argument in the form of "key=value".
# Returns the value associated with the key.
#
get_named_arg() {
  local key="$1"
  local default="${2:-}"
  shift 2
  for pair in "$@"; do
    if [[ $pair =~ ^([^=]+)=([^=]*)$ ]] && [[ ${BASH_REMATCH[1]} == "$key" ]]; then
      printf %s "${BASH_REMATCH[2]}"
    fi
  done
  printf %s "$default"
}