diff --git a/common/args.c b/common/args.c
index 068c8d2..d7d7669 100644
--- a/common/args.c
+++ b/common/args.c
@@ -202,24 +202,31 @@
 }
 
 void arg_show_usage(FILE *fp, const struct arg_def *const *defs) {
-  char option_text[40] = { 0 };
-
   for (; *defs; defs++) {
     const struct arg_def *def = *defs;
     char *short_val = def->has_val ? " <arg>" : "";
     char *long_val = def->has_val ? "=<arg>" : "";
+    int n = 0;
 
+    // Short options are indented with two spaces. Long options are indented
+    // with 12 spaces.
     if (def->short_name && def->long_name) {
       char *comma = def->has_val ? "," : ",      ";
 
-      snprintf(option_text, 37, "-%s%s%s --%s%6s", def->short_name, short_val,
-               comma, def->long_name, long_val);
+      n = fprintf(fp, "  -%s%s%s --%s%s", def->short_name, short_val, comma,
+                  def->long_name, long_val);
     } else if (def->short_name)
-      snprintf(option_text, 37, "-%s%s", def->short_name, short_val);
+      n = fprintf(fp, "  -%s%s", def->short_name, short_val);
     else if (def->long_name)
-      snprintf(option_text, 37, "          --%s%s", def->long_name, long_val);
+      n = fprintf(fp, "            --%s%s", def->long_name, long_val);
 
-    fprintf(fp, "  %-37s\t%s\n", option_text, def->desc);
+    // Descriptions are indented with 40 spaces. If an option is 40 characters
+    // or longer, its description starts on the next line.
+    if (n < 40)
+      for (int i = 0; i < 40 - n; i++) fputc(' ', fp);
+    else
+      fputs("\n                                        ", fp);
+    fprintf(fp, "%s\n", def->desc);
 
     if (def->enums) {
       const struct arg_enum_list *listptr;