at "https://raw.githubusercontent.com/pictux/Yun_3g/master/linino_set3g.sh"
/usr/bin/curl -k https://raw.githubusercontent.com/pictux/Yun_3g/master/luci-proto-3g_svn-r9931-1_ar71xx.ipk -o /tmp/luci-proto-3g_svn-r9931-1_ar71xx.ipk
openwrtyun has that package, install it from openwrtyun is prefer. ( very important if openwrtyun got upgraded) :
opkg update
opkg remove luci-proto-3g
wget http://downloads.arduino.cc/openwrtyun/1/packages/luci-proto-3g_0.11%2Bsvn10522-1_ar71xx.ipk
opkg install luci-proto-3g_0.11+svn10522-1_ar71xx.ipk