add some structure to this bash script

Add help usage and examples. Some structural hints taken from
http://linuxcommand.org/html_text/new_script.README.html

bin/inline.sh

@@ -1,6 +1,51 @@
 #!/bin/bash
 
-function dump {
+PROGNAME=${0##*/}
+PROGDIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"
+VERSION="0.1"
+FILES=()
+
+error_exit() {
+  echo -e "${PROGNAME}: ${1:-"Unknown Error"}" >&2
+  exit 1
+}
+
+graceful_exit() {
+    exit
+}
+
+usage() {
+    echo -e "Usage: $PROGNAME [-h|--help] file.conf"
+}
+
+help_message() {
+  cat <<- _EOF_
+  $PROGNAME ver. $VERSION
+  Replace include statements with the included files
+
+  The primary use of this script is for debugging nginx
+  config files, or to provide a single config file for
+  distribution/deployment.
+
+  $(usage)
+
+  Example:
+    cd /etc/nginx
+    $PROGNAME h5bp/basics.conf
+    ### h5bp/basic.conf START
+
+    ### h5bp/directive-only/x-ua-compatible.conf START
+    add_header "X-UA-Compatible" "IE=Edge";
+    ....
+
+  Options:
+  -h, --help  Display this help message and exit.
+
+_EOF_
+  return
+}
+
+function main {
     echo "### $1 START"
     while read line
     do
@@ -14,7 +59,7 @@ function dump {
             continue
         elif [[ $line =~ ^(\s*)include\s*(.*)\; ]];
         then
-            dump ${BASH_REMATCH[2]}
+            main ${BASH_REMATCH[2]}
         else
             echo "$line"
         fi
@@ -22,4 +67,24 @@ function dump {
     echo "### $1 END"
 }
 
-dump $1
+# Parse command-line
+while [[ -n $1 ]]; do
+  case $1 in
+    -h | --help)
+      help_message; graceful_exit ;;
+    -* | --*)
+      usage
+      error_exit "Unknown option $1" ;;
+    *)
+      FILES+=($1);;
+  esac
+  shift
+done
+
+if [ ${#FILES[@]} -eq 0 ];
+then
+      usage;
+      graceful_exit;
+fi
+
+main $FILES