FreeNAS drive identification

#!/usr/bin/env python
#
# FreeNAS drive identification
# based on a shell script by @Bidule0hm

import subprocess

print '''\
+========+============================================+====================+
| Device | GPTID                                      |   Serial Number    |
+========+============================================+====================+'''

drives = subprocess.check_output(['sysctl', '-n', 'kern.disks']).split()
drives.sort()

for drive in drives:
    try:
        gptid = subprocess.check_output(['glabel', 'status', '-s', drive+'p2']).split()[0]
    # not partitioned?
    except subprocess.CalledProcessError:
        gptid = 'N/A'

    try:
        serial = filter(
            lambda line: 'umber' in line,
            subprocess.check_output(['smartctl', '-i', '/dev/'+drive]).splitlines()
            )[0]
        serial = serial.split()[2]
    # SMART not supported?
    except subprocess.CalledProcessError:
        serial = 'N/A'

    print '|{0:^8}|{1:^44}|{2:^20}|'.format(drive, gptid, serial)
    print '+--------+--------------------------------------------+--------------------+'