diff --git a/dotfiles/lib/python/merge_zsh_history.py b/dotfiles/lib/python/merge_zsh_history.py
new file mode 100644
index 00000000..c7b5def4
--- /dev/null
+++ b/dotfiles/lib/python/merge_zsh_history.py
@@ -0,0 +1,32 @@
+import re
+
+history_entry_re = re.compile(": ([0-9]*):[0-9]*;.*")
+
+def merge_history(filenames):
+    pairs = [entry for filename in filenames for entry in entry_timestamp_pairs(filename)]
+    return "".join([p[0] for p in sorted(pairs, key=lambda pair: pair[1])])
+
+
+def entry_timestamp_pairs(filename):
+    pairs = []
+    with open(filename, 'r') as file:
+        entry = None
+        timestamp = None
+        for line in file.readlines():
+            if line[0] == ":":
+                if entry != None:
+                    pairs.append((entry, timestamp))
+                timestamp = timestamp_from_line(line)
+                entry = line
+            else:
+                entry += line
+    return pairs
+
+
+def timestamp_from_line(line):
+    return int(history_entry_re.search(line).group(1))
+
+
+if __name__ == '__main__':
+    import sys
+    print merge_history(sys.argv[1:])