feat(help): add help function

script

@@ -1,7 +1,22 @@
 #!/bin/sh
 
 usage() {
-	printf "Usage: %s [options]\n" "$0"
+	printf "Usage: %s [-h]\n" "$0"
+}
+
+help() {
+    cat << EOH
+ SYNOPSIS
+    $0 [-h]
+
+ DESCRIPTION
+
+    $0 does things!
+
+ OPTIONS
+
+    -h    Show this help
+EOH
 }
 
 on_interrupt() {
@@ -13,7 +28,7 @@ on_interrupt() {
 main() {
 	while getopts "hf:" option; do
 		case "${option}" in
-			h) usage; exit 0;;
+			h) help; exit 0;;
 			f) FOO="$OPTARG";;
 			*) usage; exit 1;;
 		esac