My network is bad today. I try to install some bluetooth utility from apt-get. But it take so long to complete only one dependency file. It may take an hour or more..
So, to use proxy with apt-get. Please follow below step
1) Change to apt configuration directory.
pi@raspberrypi ~ $ cd /etc/apt/apt.conf.d
2) Create new file ’10proxy’
pi@raspberrypi ~ $ sudo nano -w 10proxy
3) Put this line and save then try your apt-get again. You don’t need to reboot.
if your proxy have authenticate please use this instead.