Backup the complete data of any android app to your computer. Using ADB. Requires root for ADB.

backup_app_data.sh

#!/bin/bash
# This little shell script copies a backup of a certain app into the folder
# backup/ within the execution directory
# requires root via adb access

appToBackup="org.thoughtcrime.securesms" #change package name


tmpStore="tmpBackup_"$appToBackup"/"
adb devices

echo "Starting adb shell and creating Backup"
# copy the app data to sdcard
adb shell "su -c'mkdir -p /sdcard/$tmpStore;cp -r /data/data/$appToBackup /sdcard/$tmpStore;exit;exit'"
echo "adb shell closed"

# pull the backup
storeAt=`pwd`"/backup" #local folder
mkdir -p $storeAt
adb pull -p /sdcard/$tmpStore $storeAt

# remove the app data which temporarily has been stored on sdcard
adb shell "su -c 'rm -r /sdcard/$tmpStore'"