[thin_delta] -h/--help

features/thin_delta.feature

@@ -6,3 +6,24 @@ Feature: thin_delta
   Scenario: print version (--version flag)
     When I run `thin_delta --version`
     Then it should pass with version
+
+  Scenario: print help
+    When I run `thin_delta --help`
+    Then it should pass with:
+
+    """
+    Usage: thin_delta [options]
+    Options:
+      {-h|--help}
+      {-V|--version}
+    """
+
+  Scenario: print help
+    When I run `thin_delta -h`
+    Then it should pass with:
+    """
+    Usage: thin_delta [options]
+    Options:
+      {-h|--help}
+      {-V|--version}
+    """

thin-provisioning/thin_delta.cc

@@ -1,5 +1,6 @@
 #include <getopt.h>
 #include <iostream>
+#include <libgen.h>
 
 #include "version.h"
 
@@ -7,16 +8,32 @@ using namespace std;
 
 //----------------------------------------------------------------
 
+namespace {
+	void usage(ostream &out, string const &cmd) {
+		out << "Usage: " << cmd << " [options]" << endl
+		    << "Options:" << endl
+		    << "  {-h|--help}" << endl
+		    << "  {-V|--version}" << endl;
+	}
+}
+
+//----------------------------------------------------------------
+
 int main(int argc, char **argv)
 {
 	int c;
-	char const shortopts[] = "V";
+	char const shortopts[] = "hV";
 	option const longopts[] = {
+		{ "help", no_argument, NULL, 'h' },
 		{ "version", no_argument, NULL, 'V' }
 	};
 
 	while ((c = getopt_long(argc, argv, shortopts, longopts, NULL)) != -1) {
 		switch (c) {
+		case 'h':
+			usage(cout, basename(argv[0]));
+			return 0;
+
 		case 'V':
 			cout << THIN_PROVISIONING_TOOLS_VERSION << endl;
 			return 0;