github

###############################################################################
# function errecho
#
# This function outputs everything sent to it to STDERR (standard error output).
###############################################################################
function errecho() {
  printf "%s\n" "$*" 1>&2
}

###############################################################################
# function iam_list_users
#
# List the IAM users in the account.
#
# Returns:
#       The list of users names
#    And:
#       0 - If the user already exists.
#       1 - If the user doesn't exist.
###############################################################################
function iam_list_users() {
  local option OPTARG # Required to use getopts command in a function.
  local error_code
  # bashsupport disable=BP5008
  function usage() {
    echo "function iam_list_users"
    echo "Lists the AWS Identity and Access Management (IAM) user in the account."
    echo ""
  }

  # Retrieve the calling parameters.
  while getopts "h" option; do
    case "${option}" in
      h)
        usage
        return 0
        ;;
      \?)
        echo "Invalid parameter"
        usage
        return 1
        ;;
    esac
  done
  export OPTIND=1

  local response

  response=$(aws iam list-users \
    --output text \
    --query "Users[].UserName")
  error_code=${?}

  if [[ $error_code -ne 0 ]]; then
    aws_cli_error_log $error_code
    errecho "ERROR: AWS reports list-users operation failed.$response"
    return 1
  fi

  echo "$response"

  return 0
}