Below given is the steps to install BCM43142 wireless drivers in CrunchBang Linux.
sudo apt-get install linux-headers$(uname -r | grep -Po "\-[a-z].*")
sudo apt-get install build-essential dkms
sudo apt-get install linux-headers$(uname -r | grep -Po "\-[a-z].*")
sudo apt-get install build-essential dkms