Script to preconfigure new system with custom settings

preconfig.sh

#!/usr/bin/env bash
# ~*~ coding: utf-8 ~*~

##########################################
# Installing commons
##########################################

command_exist () { which $1 > /dev/null; }

# Install vim
if ( command_exist vim ); then
    echo Vim already installed
else
    echo Installing vim...
    sudo apt-get install -y vim > /dev/null
    echo Installed vim
fi

# Install tmux 
if ( command_exist tmux ); then
    echo Tmux already installed
else
    echo Installing tmux...
    sudo apt-get install -y tmux > /dev/null
    echo Installed tmux
fi

# Install tmuxinator
if ( command_exist mux ); then
    echo Mux already installed
else
    if ( command_exist gem ); then
        echo Gem already installed
    else
        echo Installing ruby...
        sudo apt-get install -y ruby > /dev/null
        echo Installed ruby
    fi
    echo Installing mux
    sudo gem install tmuxinator > /dev/null
    echo Installed mux
fi

# Install curl
if ( command_exist curl ); then
    echo Curl already installed
else
    echo Instaling curl...
    sudo apt-get install -y curl > /dev/null
fi

##########################################
# Configuring commons
##########################################

# Config vim
echo Downloading .vimrc
curl -sS https://gist.githubusercontent.com/koutoftimer/98c3554841016249a9a2/raw/dfc0a1bad19efa817ab3ed94e84a9dc573ed20af/.vimrc > ~/.vimrc

# Config tmux
echo Downloading .tmux.conf
curl -sS https://gist.githubusercontent.com/koutoftimer/9f14ebd790c2016e2f52/raw/56fe8396c3a91c92601cd97c1fa4a6f84aa5c26c/.tmux.conf > ~/.tmux.conf