This script copies all data from /data/data to any directory(in sdcard) and (soft)links back them in /data/data.
The purpose is to free space from /data/data.
To use it, first make sure the DESTDIR exists, change it according to your need, mkdir it. here i used /data/sdext2 which is a ext partition on sdcard mounted by link2sd.
make sure your android is rooted and you have cp,rm,ln binary installed, usually these come from busybox.
copy the script to android,
adb push linkappdata.sh /sdcard/
now goto shell,
adb shell
become root,
su
now run it,
sh /sdcard/linkappdata.sh
wait till it finishes.
Run the last command again if you install a new app.