diff --git a/tools/analyse.cpp b/tools/analyse.cpp
index 8a0d419..75d9133 100644
--- a/tools/analyse.cpp
+++ b/tools/analyse.cpp
@@ -17,6 +17,7 @@
 #include <algorithm>
 #include <iostream>
 #include <compare>
+#include <fstream>
 
 
 ///////////////////////////////////////////////////////////////////////////////
@@ -91,6 +92,8 @@ int main (int argc, char const **argv)
 
     std::cerr << p << '\n';
 
+    std::ofstream output (argv[ARGS_OUTPUT], std::ios::out | std::ios::trunc);
+    output.exceptions (std::ios::badbit | std::ios::eofbit | std::ios::failbit);
 
     cruft::mapped_file data (argv[ARGS_INPUT]);
     std::cout << "size: " << data.size () << '\n';