Set Variables:

admin@RT-N66U:/# nvram set apps_dev=sda1
admin@RT-N66U:/# nvram set apps_mounted_path=/tmp/mnt/STICK

Replace the values with your device settings. Use mount to get them.

Execute Script:

admin@RT-N66U:/# /usr/sbin/app_base_link.sh

This example installs the irc proxy called miau:

admin@RT-N66U:/# /usr/sbin/app_install.sh miau

To get a list of all available applications:

admin@RT-N66U:/# ipkg list