diff --git a/demos/sizes.c b/demos/sizes.c
index bc3f8a5..c2c07ef 100644
--- a/demos/sizes.c
+++ b/demos/sizes.c
@@ -6,8 +6,14 @@
  * The library is free for all purposes without any express
  * guarantee it works.
  */
+
 #include "tomcrypt.h"
 
+#if _POSIX_C_SOURCE >= 200112L
+#include <libgen.h>
+#else
+#define basename(x) x
+#endif
 /**
   @file demo_crypt_sizes.c
 
@@ -15,29 +21,57 @@
   like Python - Larry Bugbee, February 2013
 */
 
+static void _print_line(const char* cmd, const char* desc)
+{
+   printf("  %-16s - %s\n", cmd, desc);
+}
 
-int main(void) {
+int main(int argc, char **argv)
+{
+   if (argc == 1) {
+      /* given a specific size name, get and print its size */
+      char name[] = "ltc_hash_descriptor";
+      unsigned int size;
+      char *sizes_list;
+      unsigned int sizes_list_len;
+      if (crypt_get_size(name, &size) != 0) exit(EXIT_FAILURE);
+      printf("\n  size of '%s' is %u \n\n", name, size);
 
-    /* given a specific size name, get and print its size */
-    char name[] = "ltc_hash_descriptor";
-    unsigned int size;
-    char *sizes_list;
-    unsigned int sizes_list_len;
-    if(crypt_get_size(name, &size) != 0)
-      exit(EXIT_FAILURE);
-    printf("\n  size of '%s' is %u \n\n", name, size);
+      /* get and print the length of the names (and sizes) list */
+      if (crypt_list_all_sizes(NULL, &sizes_list_len) != 0) exit(EXIT_FAILURE);
+      printf("  need to allocate %u bytes \n\n", sizes_list_len);
 
-    /* get and print the length of the names (and sizes) list */
-    if(crypt_list_all_sizes(NULL, &sizes_list_len) != 0)
-       exit(EXIT_FAILURE);
-    printf("  need to allocate %u bytes \n\n", sizes_list_len);
-
-    /* get and print the names (and sizes) list */
-    sizes_list = malloc(sizes_list_len);
-    if(crypt_list_all_sizes(sizes_list, &sizes_list_len) != 0)
-       exit(EXIT_FAILURE);
-    printf("  supported sizes:\n\n%s\n\n", sizes_list);
-    return 0;
+      /* get and print the names (and sizes) list */
+      sizes_list = malloc(sizes_list_len);
+      if (crypt_list_all_sizes(sizes_list, &sizes_list_len) != 0) exit(EXIT_FAILURE);
+      printf("  supported sizes:\n\n%s\n\n", sizes_list);
+   } else if (argc == 2) {
+      if (strcmp(argv[1], "-h") == 0 || strcmp(argv[1], "--help") == 0) {
+         char* base = strdup(basename(argv[0]));
+         printf("Usage: %s [-a] [-s name]\n\n", base);
+         _print_line("<no argument>", "The old behavior of the demo");
+         _print_line("-a", "Only lists all sizes");
+         _print_line("-s name", "List a single size given as argument");
+         _print_line("-h", "The help you're looking at");
+         free(base);
+      } else if (strcmp(argv[1], "-a") == 0) {
+         char *sizes_list;
+         unsigned int sizes_list_len;
+         /* get and print the length of the names (and sizes) list */
+         if (crypt_list_all_sizes(NULL, &sizes_list_len) != 0) exit(EXIT_FAILURE);
+         /* get and print the names (and sizes) list */
+         sizes_list = malloc(sizes_list_len);
+         if (crypt_list_all_sizes(sizes_list, &sizes_list_len) != 0) exit(EXIT_FAILURE);
+         printf("%s\n", sizes_list);
+      }
+   } else if (argc == 3) {
+      if (strcmp(argv[1], "-s") == 0) {
+         unsigned int size;
+         if (crypt_get_size(argv[2], &size) != 0) exit(EXIT_FAILURE);
+         printf("%s,%u\n", argv[2], size);
+      }
+   }
+   return 0;
 }
 
 /* ref:         $Format:%D$ */