Install R 3.4.0 from source on ubuntu 16.04

This tutorial is modified from https://askubuntu.com/questions/798335/how-you-install-r-3-2-2-in-ubuntu-14-04-lts

cd $HOME
wget https://cran.rstudio.com/src/base/R-3/R-3.4.0.tar.gz
tar xvf R-3.4.0.tar.gz
cd R-3.4.0
sudo apt-get install gcc fort77 aptitude
sudo aptitude install g++
sudo aptitude install xorg-dev
sudo aptitude install libreadline-dev
sudo aptitude install gfortran
gfortran --version
sudo apt install libpcre3-dev liblzma-dev libbz2-dev
sudo add-apt-repository ppa:webupd8team/java -y
sudo apt-get update
sudo apt-get install oracle-java8-installer
sudo apt-get install oracle-java8-set-default
sudo apt-get install texlive-base
sudo apt-get install texinfo
sudo apt-get install texlive-fonts-extra
sudo apt-get install libcurl4-openssl-dev
java -version
# need to build shared library (--enable-R-shlib)
# the --enable-R-shlib option is needed for the RStudio IDE to work
sudo ./configure --enable-R-shlib      
sudo make
sudo make install
R --version
cd $HOME
rm R-3.4.0.tar.gz
sudo rm -rf R-3.4.0

Now you can install Rstudio:

wget https://download1.rstudio.org/rstudio-1.0.143-i386.deb
sudo gdebi -n rstudio-1.0.143-i386.deb

rm rstudio-1.0.143-i386.deb

No ssh connection: REMOTE HOST IDENTIFICATION HAS CHANGED

When you try to connect using ssh in terminal to a remote host, if you get this message:
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
@    WARNING: REMOTE HOST IDENTIFICATION HAS CHANGED!     @
@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@@
IT IS POSSIBLE THAT SOMEONE IS DOING SOMETHING NASTY!
Someone could be eavesdropping on you right now (man-in-the-middle attack)!
It is also possible that a host key has just been changed.
The fingerprint for the ECDSA key sent by the remote host is
SHA256:wJp/vYtoiAonG/LRyXK6fYuzcCb7WQZF1N9tlxVVOsg.
Please contact your system administrator.


you must edit this file:
sudo vi ~/.ssh/known_hosts
And remove the line corresponding to the faulty ip address.