GSWL Part 2: Compiling Dependencies for Bitcoin Based Cryptocurrencies

Table of Contents

Part 2 of GSWL is fairly more complicated than part 1. We are looking at how to prep our Linux install for compiling various Bitcoin based cryptocurrencies from source code. That means that we are heading into rabbit hole that goes farther back than 2011. If for nothing else, you need to know how to compile the Berkeley4.8db independently. Hopefully my directions on that below save you from pulling your hair out.

New Terminal Commands

The "cd" Command

"cd" is short for change directory, and its the only method to navigate between folders in almost any command line. Despite being so common, cd is a bit complicated at first. To fully understand how cd works, we need to examine how file systems work. We can look at our file system like a pyramid, at the top of the pyramid you find whats called your "root" directory. In Linux (and most operating systems) it is expressed as "/", thats it. This directory most commonly requires significant privledges to add files to, and hardly ever has files added to it directly due to security concerns. Below that level we have a few levels that run simultaniously: user containers, OS containers, and shared libraries/software containers.

These are all exactly what you would expect them to be. The user container contains all the data specific to a specific user, often each user has their own container. The location for the user container that is logged in to any system based on Unix is almost always "~". The OS container holds all the core operating system files. Often this container is protected as well to prevent security issues. When you install a piece of software you usually install it to the shared software container or the user container. Almost never do you install to the OS container itself.

Finally the shared software/libraries container is where all the things that users install to the computer, and not to their specific user account, get installed. It is accessible to all user accounts on a computer, not just the user logged in at the time. Below these levels we get into all kinds of smaller and much more multitudinous folders and files. Really we don't need to bother with knowing that part of the analogy.

The important thing to know is that we are moving up and down in the system. Up is toward the "root" or "/" location, and down is toward specific files. When you open a terminal window in Linux, you are usually taken to the default location, or "~". This location, "~" is the top of your user container. Here is where commands that download files will default to download them to. They wont default to downloading them to "/" nor should they, as that could put your computers security at risk. "~" can be looked at as the top of a pyramid that just contains your stuff. Its technically found in Ubuntu at /home/USERNAME/, but in terminal windows it will display as "~". To mitigate risk, you should never use sudo with any command that downloads a remote file other than verified repositories.

"~" and "/"

To move between "~" and "/" all you need to do is either use cd / or cd ~. You will see the active directory (to the left of the $ in terminal) update as you move around. To go up a folder simply use cd .. and to go down a folder use cd FOLDERNAME. You can also navigate to places from a distance by typing in the full folder location like cd /usr/local/bin or cd ~/Desktop/Litecoin. Its important to note that capitalization is read by cd, so ~/desktop is not the same as ~/Desktop.

The "LS" command

As important as cd is, it doesn't help anyone at all without the ls command. ls is the command to simply list all the files within the directory. This is really helpful when combined with the cd command as it allows you to find the name of directories within the folder you are in.

The "make" command

Make is used to compile source code into binaries. Usually you need to run a configuration script, or an autogen script prior to running make. Once you run make, you then need to install the binaries by running make install. Make is folder specific, so if you move folders between running make and make install, you will have to go back to the original folder to get make install to work. Also, you can control how many simultaneous build tasks make runs by using the -j modifier(i.e. make -j 2). The number for -j should never exceed your number of cores minus one.

The ". /" Command

"./" is less of a command, and more of an instruction. Basically you use ./ before a script or binary to make the script or binary execute. So if you have a binary named "litecoin-qt", you would run it from terminal by entering ./litecoin-qt. Running the command as ../ will let you specify a folder at the same level as the one you are in and then a script within it to run. This comes in handy when compiling, and we will see it within the Berkeley4.8db compilation instructions.

The "wget" Command

wget is a command that allows us to download a file to the active directory. It has it's uses alongside git and other download commands, we will use it when we compile our local copy of the Berkeley4.8db.

The "unzip" Command

unzip does what it says it does, it unzips a compressed file. With no modifiers, it will extract all of the contents of the specified file to the current active directory.

The "git" Command

The command git comes to us through a new package we will install later on in this tutorial. Essentially git allows us to download whole repositories from Github, instead of just a single file like wget.

Basic Dependencies for Cryptocurrencies

For this part of GSWL we will be working with a brand new installation of Ubuntu 20.04.1 LTS on a Parallels VM run on a MacBook Pro. Your mileage on any other system, distro, or VM platform may vary. We will be walking through how to compile from source the Litecoin wallet. This process should get you about 99% of the dependencies you need to compile other Altcoins on your systems.

Software to Install from the Software Package

There are a few things we will want to go ahead and grab while we are in the Software application. Start your search by clicking on the magnifying glass icon in the upper left hand corner.

Sublime Text

Sublime Text is a text editor program. It will come in handy in a lot of ways, but mostly for average users will be good for creating .conf files for miners or other packages that require them.

Dependencies to Download From Terminal for Cryptocurrencies

There are quite a few dependencies you will need to grab from terminal to get ready to compile Litecoin. The ones below are all you need to compile Litecoin. However, you will likely need to add others with different Altcoins. I'll show you how to find those needs as we go through the process.

Libssl

Libssl is a library that contains a random number generator as well as some other cryptographic tools. This is obviously important as we are dealing with Cryptocurrencies and cryptography is the core of this technology.

$ sudo apt install libssl-dev

Libboost

Libboost is a library that helps applications structure themselves correctly. A quick word of warning, there are a lot of versions of libboost out there. Some Altcoins are built correctly and look for the most recent version of boost. Some pre-built binaries are not built correctly and are looking for older versions. This is part of the reason that everyone should know how to compile from source. It prevents this kind of nonsense with versions of dependencies. That said, there are some dependencies that are globally version specific and have to be found in weird ways.

$ sudo apt install libboost1.71-all-dev

Libevent

Libevent is a library for allowing compiled software to communicate with network devices. It is most likely already installed on your computer already, but if not you'll want to use the command below to install it.

$ sudo apt install libevent-dev

Miniupnpc

Miniupnpc allows for applications to support UPnP to help navigate firewalls.

$ sudo apt install libminiupnpc-dev

Libdb4.8

This is the infamous Berkeley4.8db that is used by every Altcoin that is based on Bitcoin. It is not available using Aptitude, nor can you obtain it by using the common directions of adding the Bitcoin PPA. Instead, you'll need to follow the second set of instructions from Crypto and Coffee that I have copied below.

$ wget http://download.oracle.com/berkeley-db/db-4.8.30.zip

$ unzip db-4.8.30.zip

$ cd db-4.8.30

$ cd build_unix

$ ../dist/configure --prefix=/usr/local --enable-cxx

$ sudo make

$ sudo make install

If you happen to follow the first set on that site, you will be greeted by the error below, and then have to go into the Software & Updates program to remove the PPA from the Software Sources tab, lest you want to see that error every time you run apt update or apt-get update.