cabal update fails

Problem: 

After installing cabal, running 

$ cabal update

shows an error message 

Command 'cabal' not found, but can be installed with:

sudo apt install cabal-install

Solution: 

Add ~/.local/bin and ~/.cabal/bin to the PATH

Open your .bashrc and add the following lines at the bottom:

export PATH="~/.cabal/bin:$PATH"
export PATH="~/.local/bin:$PATH"

Save the changes, and source your .bashrc file  

$ source .bashrc

Now will be able to run cabal update

$ cabal update 

> Downloading the latest package list from hackage.haskell.org
...