diff --git a/fancontrol.py b/fancontrol.py
index 7eb9ebc..e3e8332 100755
--- a/fancontrol.py
+++ b/fancontrol.py
@@ -1,85 +1,116 @@
 #!/usr/bin/env python
+# -*- coding: utf8 -*-
+
+import os
 import sys
 import time
 import glob
+import stat
 
 try:
     from StringIO import StringIO
 except ImportError:
     from io import StringIO
-from subprocess import check_output, Popen, PIPE, STDOUT
+
+from subprocess import check_output, Popen, PIPE, STDOUT, CalledProcessError
+
+devices_to_check = ['/dev/sg*', '/dev/ses*']
+
+
+def usage():
+    print('python fancontrol.py 1-7')
+    sys.exit(-1)
+
+
+def get_requested_fan_speed():
+    if len(sys.argv) < 2:
+        return usage()
+    try:
+        speed = int(sys.argv[1])
+    except ValueError:
+        return usage()
+    if not 1 <= speed <= 7:
+        return usage()
+    return speed
 
 
 def print_speeds(device):
     for i in range(0, 6):
-        print("Fan {} speed: {}".format(i, check_output(
+        print('Fan {} speed: {}'.format(i, check_output(
             ['sg_ses', '--index=coo,{}'.format(i), '--get=1:2:11', device]).decode('utf-8').split('\n')[0]))
 
 
-if len(sys.argv) < 1:
-    print("python fancontrol.py 1-7")
-    sys.exit(-1)
+def find_sa120_devices():
+    devices = []
+    for device_glob in devices_to_check:
+        for device in glob.glob(device_glob):
+            try:
+                output = check_output(['sg_ses', device], stderr=STDOUT)
+                if b'ThinkServerSA120' in output:
+                    print('Enclosure found on ' + device)
+                    devices.append(device)
+                else:
+                    print('Enclosure not found on ' + device)
+            except CalledProcessError:
+                print('Enclosure not found on ' + device)
+    return devices
 
-fan = int(sys.argv[1])
 
-if fan <= 0 or fan > 6:
-    raise Exception("Fan speed must be between 1 and 7")
+def set_fan_speeds(device, speed):
+    print_speeds(device)
+    print('Reading current configuration...')
+    out = check_output(['sg_ses', '-p', '0x2', device, '--raw']).decode('utf-8')
 
-devices_to_check = ['/dev/sg*', '/dev/ses*']
+    s = out.split()
 
-device = ""
+    for i in range(0, 6):
+        print('Setting fan {} to {}'.format(i, speed))
+        idx = 88 + 4 * i
+        s[idx + 0] = '80'
+        s[idx + 1] = '00'
+        s[idx + 2] = '00'
+        s[idx + 3] = format(1 << 5 | speed & 7, 'x')
 
-for device_glob in devices_to_check:
-    for dev_node in glob.glob(device_glob):
-        try:
-            out = check_output(["sg_ses", dev_node], stderr=STDOUT)
-            if 'ThinkServerSA120' in out:
-                device = dev_node
-                print("Enclosure found on " + device)
+    output = StringIO()
+    off = 0
+    count = 0
 
-                print_speeds(device)
-                print("Reading current configuration...")
-                out = check_output(["sg_ses", "-p", "0x2", device, "--raw"]).decode('utf-8')
-                s = out.split()
+    while True:
+        output.write(s[off])
+        off = off + 1
+        count = count + 1
+        if count == 8:
+            output.write('  ')
+        elif count == 16:
+            output.write('\n')
+            count = 0
+        else:
+            output.write(' ')
+        if off >= len(s):
+            break
 
-                for i in range(0, 6):
-                    print("Setting fan {} to {}".format(i, fan))
-                    idx = 88 + 4 * i
-                    s[idx + 0] = "80"
-                    s[idx + 1] = "00"
-                    s[idx + 2] = "00"
-                    s[idx + 3] = format(1 << 5 | fan & 7, "x")
+    output.write('\n')
+    p = Popen(['sg_ses', '-p', '0x2', device, '--control', '--data', '-'], stdout=PIPE, stdin=PIPE,
+              stderr=PIPE)
+    print('Set fan speeds... Waiting to get fan speeds (ctrl+c to skip)')
+    print(p.communicate(input=bytearray(output.getvalue(), 'utf-8'))[0].decode('utf-8'))
+    try:
+        time.sleep(10)
+        print_speeds(device)
+    except KeyboardInterrupt:
+        pass
 
-                output = StringIO()
-                off = 0
-                count = 0
-                line = ''
 
-                while True:
-                    output.write(s[off])
-                    off = off + 1
-                    count = count + 1
-                    if count == 8:
-                        output.write("  ")
-                    elif count == 16:
-                        output.write("\n")
-                        count = 0
-                    else:
-                        output.write(" ")
-                    if off >= len(s):
-                        break
+def main():
+    speed = get_requested_fan_speed()
+    devices = find_sa120_devices()
+    if not devices:
+        print('Could not find enclosure')
+        sys.exit(1)
+    for device in devices:
+        set_fan_speeds(device, speed)
+    print('\nDone')
 
-                output.write("\n")
-                p = Popen(['sg_ses', '-p', '0x2', device, '--control', '--data', '-'], stdout=PIPE, stdin=PIPE,
-                          stderr=PIPE)
-                print("Set fan speeds... Waiting to get fan speeds (ctrl+c to skip)")
-                print(p.communicate(input=bytearray(output.getvalue(), 'utf-8'))[0].decode('utf-8'))
-                time.sleep(10)
-                print_speeds(device)
-        except:
-            print("Enclosure not found on " + dev_node)
-
-if device == "":
-    print("Could not find enclosure")
-    sys.exit(1)
 
+if __name__ == '__main__':
+    main()