Install tig from source

upgrade_tig.sh

#!/bin/bash

if which apt-get 2>&1 >/dev/null; then
  [[ -z $(dpkg --get-selections | grep libncursesw5-dev) ]] && sudo apt-get install -y libncursesw5-dev
elif which brew 2>&1 >/dev/null; then
  brew install tig --with-docs
  exit
fi


cd ~/src

[[ ! -d tig ]] && git clone git://github.com/jonas/tig.git --depth 10

cd tig
git fetch origin tig-2.1.1 --depth 1
git checkout FETCH_HEAD

make configure
./configure

# install for all users
make prefix=/usr/local all
sudo make prefix=/usr/local install

sudo make install-release-doc