diff --git a/src/util.cr b/src/util.cr
index bc97887..a3fad38 100644
--- a/src/util.cr
+++ b/src/util.cr
@@ -99,3 +99,16 @@ end
 def random_str
   UUID.random.to_s.gsub "-", ""
 end
+
+# Works in all Unix systems. Follows https://github.com/crystal-lang/crystal/
+#   blob/master/src/crystal/system/unix/file_info.cr#L42-L48
+def ctime(file_path : String) : Time
+  res = LibC.stat(file_path, out stat)
+  raise "Unable to get ctime of file #{file_path}" if res != 0
+
+  {% if flag?(:darwin) %}
+    Time.new stat.st_ctimespec, Time::Location::UTC
+  {% else %}
+    Time.new stat.st_ctim, Time::Location::UTC
+  {% end %}
+end