This script copies all data from /data/data to any directory(in sdcard) and (soft)links back them in /data/data.

README

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.

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.

linkappdata.sh

#!/system/bin/sh
cd /data/data
DESTDIR=/data/sdext2/skdata/
for DIRS in `find . -mindepth 1 -maxdepth 1 -type d`
do
    cp -r $DIRS /data/sdext2/skdata/
    rm -r $DIRS
    ln -s /data/sdext2/skdata/$DIRS $DIRS

done

echo finished