This simple script will backup user installed android applications to the computer. Extremely useful when there is not enough space in the phone. Requires working 'adb shell'.

backup_android_user_packages

#!/usr/bin/env python
import subprocess

adb_process = subprocess.Popen(
    'adb shell pm list packages -f', shell=True, stdout=subprocess.PIPE)

user_packages = []

while True:
    output_line = adb_process.stdout.readline().strip()
    if len(output_line) == 0:
        break
    if 'data' in output_line:
        user_packages.append(output_line)

for fpath, fname in [(x.split(':')[1].split('=')[0], x.split('=')[1] + '.apk') for x in user_packages]:
    subprocess.Popen('adb pull %s %s' %
                     (fpath, fname), shell=True, stdout=subprocess.PIPE)
    # adb_output, adb_error = process.communicate()

# print user_packages
# adb_output, adb_error = process.communicate()

Learn how to use adb backup to save app data as well when the mobile is rooted.