diff --git a/zenstates.py b/zenstates.py
index db9ab3a..9ee16ac 100755
--- a/zenstates.py
+++ b/zenstates.py
@@ -9,7 +9,7 @@
 def writemsr(msr, val, cpu = -1):
     try:
         if cpu == -1:
-            for c in glob.glob('/dev/cpu/[0-9]*/msr'):
+            for c in glob.glob('/dev/cpu/%d/msr'):
                 f = os.open(c, os.O_WRONLY)
                 os.lseek(f, msr, os.SEEK_SET)
                 os.write(f, struct.pack('Q', val))