diff --git a/main.c b/main.c
index 962bd49..a03cb19 100644
--- a/main.c
+++ b/main.c
@@ -743,8 +743,10 @@ main (int argc, char *argv[])
         const char *sce = argv[i];
         size_t scelen = strlen(sce);
 
-        if (strcmp(sce + scelen - 3, ".md"))
-            errx(-ERR_IO, "cannot convert '%s': File must be a markdown file (*.md)", sce);
+        if (strcmp(sce + scelen - 3, ".md")) {
+            warn("Skipping '%s': File must be a markdown file (*.md)", sce);
+            continue;
+        }
 
         char dst[scelen + 3];
         memcpy(dst, sce, scelen - 2);