diff --git a/swash/processing/read_swash.py b/swash/processing/read_swash.py
index 9ae9d29..2c0936c 100644
--- a/swash/processing/read_swash.py
+++ b/swash/processing/read_swash.py
@@ -16,10 +16,14 @@ class ReadSwash:
 
     @classmethod
     def read_nohead(cls, path):
-        log.info(f"Replacing \\s with \\n in '{path}'")
-        subprocess.run(("sed", "-i", r"s/\s\+/\n/g", path))
-        log.info(f"Loading '{path}'")
-        return np.loadtxt(path)
+        with tempfile.TemporaryFile(mode="w+t") as tmpfile:
+            log.info(f"Replacing \\s with \\n in '{path}'")
+            subprocess.run(("sed", r"s/\s\+/\n/g;/^$/d", path), stdout=tmpfile, text=True)
+            log.info(f"Loading '{path}'")
+            tmpfile.seek(0)
+            a = np.asarray(tmpfile.readlines(), dtype=float)
+            log.debug(f"path={a}")
+            return a
 
     def read_time(self, path):
         self._t = np.unique(self.read_nohead(path))