diff --git a/elastic_recheck/cmd/graph.py b/elastic_recheck/cmd/graph.py
index da1388ad..e5d60705 100755
--- a/elastic_recheck/cmd/graph.py
+++ b/elastic_recheck/cmd/graph.py
@@ -18,7 +18,6 @@ import argparse
 from datetime import datetime
 import json
 import os
-import sys
 
 from launchpadlib import launchpad
 import pyelasticsearch
@@ -43,6 +42,7 @@ import elastic_recheck.elasticRecheck as er
 from elastic_recheck import log as logging
 import elastic_recheck.query_builder as qb
 import elastic_recheck.results as er_results
+from elastic_recheck.utils import atomic_write
 
 STEP = 3600000
 
@@ -237,15 +237,9 @@ def main():
                      key=lambda bug: -(bug['fails24'] * 100000 + bug['fails']))
 
     jsondata['buglist'] = buglist
-    if args.output:
-        out = open(args.output, 'w')
-    else:
-        out = sys.stdout
-
-    try:
-        out.write(json.dumps(jsondata))
-    finally:
-        out.close()
+    atomic_write(
+        args.output,
+        json.dumps(jsondata))
 
 
 if __name__ == "__main__":
diff --git a/elastic_recheck/cmd/uncategorized_fails.py b/elastic_recheck/cmd/uncategorized_fails.py
index f65eaf66..6b8f993b 100755
--- a/elastic_recheck/cmd/uncategorized_fails.py
+++ b/elastic_recheck/cmd/uncategorized_fails.py
@@ -30,6 +30,7 @@ import elastic_recheck.config as er_config
 import elastic_recheck.elasticRecheck as er
 import elastic_recheck.query_builder as qb
 import elastic_recheck.results as er_results
+from elastic_recheck.utils import atomic_write
 
 LOG = logging.getLogger('eruncategorized')
 
@@ -370,14 +371,14 @@ def main():
                             'ALL_FAILS_QUERY might be broken.', group)
             continue
         data = collect_metrics(classifier, fails, config=config)
+        LOG.info(
+            "Using templates from %s for %s group",
+            opts.templatedir, group)
         engine = setup_template_engine(opts.templatedir, group=group)
         html = classifying_rate(fails, data, engine, classifier, config.ls_url)
-        if opts.output:
-            out_dir = opts.output
-        else:
-            out_dir = os.getcwd()
-        with open(os.path.join(out_dir, group + '.html'), "w") as f:
-            f.write(html)
+        atomic_write(
+            os.path.join(opts.output or os.getcwd(), group + '.html'),
+            html)
 
 
 if __name__ == "__main__":
diff --git a/elastic_recheck/utils.py b/elastic_recheck/utils.py
new file mode 100644
index 00000000..38dd746b
--- /dev/null
+++ b/elastic_recheck/utils.py
@@ -0,0 +1,16 @@
+import os
+import sys
+from typing import Optional
+
+
+def atomic_write(filename: Optional[str], data: str) -> None:
+    """Atomically writes a file.
+
+    If filename is not mentioned, it will write to sys.stdout
+    """
+    if filename:
+        with open(f"{filename}.tmp", "w") as f:
+            f.write(data)
+        os.replace(f"{filename}.tmp", filename)
+    else:
+        sys.stdout.write(data)