diff --git a/src/slic3r.cpp b/src/slic3r.cpp
index 9cde583f3..ebdebf9ab 100644
--- a/src/slic3r.cpp
+++ b/src/slic3r.cpp
@@ -17,6 +17,7 @@
 #include <boost/filesystem.hpp>
 #include <boost/nowide/args.hpp>
 #include <boost/nowide/iostream.hpp>
+#include <stdexcept>
 
 #ifdef USE_WX
     #include "GUI/GUI.hpp"
@@ -48,8 +49,6 @@ int CLI::run(int argc, char **argv) {
         return 1;
     }
     
-    // TODO: validate this->config (min, max etc.)
-    
     // parse actions and transform options
     for (auto const &opt_key : opt_order) {
         if (cli_actions_config_def.has(opt_key)) this->actions.push_back(opt_key);
@@ -293,7 +292,7 @@ int CLI::run(int argc, char **argv) {
                 const std::string outfile = this->output_filepath(model, IO::Gcode);
                 try {
                     print.export_gcode(outfile);
-                } catch (InvalidPrintException &e) {
+                } catch (std::runtime_error &e) {
                     boost::nowide::cerr << e.what() << std::endl;
                     return 1;
                 }
diff --git a/xs/src/libslic3r/Print.cpp b/xs/src/libslic3r/Print.cpp
index c6769c2cc..64dadeb2b 100644
--- a/xs/src/libslic3r/Print.cpp
+++ b/xs/src/libslic3r/Print.cpp
@@ -9,7 +9,17 @@
 #include <algorithm>
 #include <boost/filesystem.hpp>
 #include <boost/lexical_cast.hpp>
+#include <cstdio>
+#include <cstdlib>
 #include <fstream>
+#include <thread>
+#include <sstream>
+
+#ifdef __cpp_lib_quoted_string_io
+    #include <iomanip>
+#else
+    #include <boost/algorithm/string.hpp>
+#endif
 
 namespace Slic3r {
 
@@ -717,7 +727,6 @@ Print::export_gcode(std::ostream& output, bool quiet)
 
     auto export_handler {Slic3r::PrintGCode(*this, output)};
     export_handler.output();
-
 }
 
 void
@@ -726,10 +735,46 @@ Print::export_gcode(std::string outfile, bool quiet)
     // compute the actual output filepath
     outfile = this->output_filepath(outfile);
     
-    std::ofstream outstream(outfile);
+    // write G-code to a temporary file in order to make the export atomic
+    const std::string tempfile{ outfile + ".tmp" };
+    std::ofstream outstream(tempfile);
     this->export_gcode(outstream);
     
-    // TODO: export_gcode() is not ported completely from Perl
+    // rename the temporary file to the destination file
+    // When renaming, some other application (thank you, Windows Explorer) 
+    // may keep the file locked. Try to wait a bit and then rename the file again.
+    for (int i = 0; std::rename(tempfile.c_str(), outfile.c_str()) != 0; ++i) {
+        if (i == 4) {
+            std::stringstream ss;
+            ss << "Failed to remove the output G-code file from "
+                << tempfile << " to " << outfile << ". Is " << tempfile << " locked?";
+            throw std::runtime_error(ss.str());
+        } else {
+            // Wait for 1/4 seconds and try to rename once again.
+            std::this_thread::sleep_for(std::chrono::milliseconds(250));
+        }
+    }
+    
+    // run post-processing scripts
+    if (!this->config.post_process.values.empty()) {
+        if (this->status_cb != nullptr) 
+            this->status_cb(95, "Running post-processing scripts...");
+        
+        this->config.setenv_();
+        for (std::string ppscript : this->config.post_process.values) {
+            #ifdef __cpp_lib_quoted_string_io
+                ppscript += " " + std::quoted(outfile);
+            #else
+                boost::replace_all(ppscript, "\"", "\\\"");
+                ppscript += " \"" + outfile + "\"";
+            #endif
+            system(ppscript.c_str());
+        
+            // TODO: system() should be only used if user enabled an option for explicitly
+            // supporting arguments, otherwise we should use exec*() and call the executable
+            // directly without launching a shell. #4000
+        }
+    }
 }