sudo apt update
sudo apt install git cmake libusb-1.0-0-dev

RPITX Install:

git clone https://github.com/F5OEO/rpitx
cd rpitx
./install.sh

RTL-SDR Install:

git clone https://github.com/keenerd/rtl-sdr
cd rtl-sdr
mkdir build
cd build
cmake ../ -DINSTALL_UDEV_RULES=ON
make
sudo make install 
sudo ldconfig
sudo reboot

To Record The Key Fob Signal:

cd rpitx
rtl_sdr -s 250000 -g 35 -f 315.0125e6 unlock.iq

To Transmit The Key Fob Signal:

sudo ./sendiq -s 250000 -f 315.0125e6 -t u8 -i unlock.iq