**Installing MacPorts on Ubuntu Linux**

----

MacPorts has been designed to be multi-platform, and it does install on Ubuntu Linux with modest modifications. Please note that at this point in time, this is a highly experimental process, and issues are expected to arise.

First, some quick notes for those familiar with Darwin;   on Ubuntu:

apt is the built-in package manager, similar to "port".

"sudo apt install" is similar to "sudo port install".

"apt info" is similar to "port info"

"apt-file show" does something similar to "port contents", but the software does not have to be installed.


To install MacPorts on Ubuntu Linux, you must first install the necessary prerequisites that are typically found on Darwin systems. At the time of writing, this was:
{{{
sudo apt install clang-9
sudo apt install clang
sudo apt install mtree-netbsd
sudo apt install tcl8.6
sudo apt install curl
sudo apt install sqlite3
sudo apt install gnustep
sudo apt install libcurl4-gnutls-dev
sudo apt install libsqlite3-dev
sudo apt install libssl-dev
}}}
or, all at once:
{{{
sudo apt install clang-9 clang mtree-netbsd tcl8.6 curl sqlite3 gnustep libcurl4-gnutls-dev libsqlite3-dev libssl-dev
}}}

Note: there has been a conflict noted with {{{libmd-dev}}} when installing base; just disable that temporarily to install MacPorts. There could easily be other such conflicts not yet discovered.

Then download the macports tarball  from macports.org, perhaps using the included FireFox browser, and decompress it, as per the usual Darwin instructions <https://www.macports.org/install.php#source>. 

I suggest that you don't install startup items at this point in time, as this functionality is different on Ubuntu, so configure your build like this:
{{{
./configure --without-startupitems
}}}
and then 
{{{
make && sudo make install
}}}

Then add the "macports" user, in the Ubuntu way:
{{{
sudo adduser --system --group --home /opt/local/var/macports/home  --disabled-password macports
sudo chown -R macports:macports /opt/local/var/macports/home
}}}

Add the macports directory to your PATH as usual, but on Ubuntu, by editing ".bashrc", for example with {{{nano}}}, adding a line like this:
{{{
export PATH=/opt/local/bin:/opt/local/sbin:$PATH
}}}

Also add that PATH to the sudo command's path, like this:
{{{
sudo visudo
}}}
and add it to the secure_path
{{{
Defaults  secure_path="/opt/local/bin:/opt/local/sbin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/snap/bin"
}}}
There are some differences between Darwin and Ubuntu, and to work around some of these that are not already compensated for by MacPorts base, set some defaults in {{{macports.conf}}} like this:

{{{
sudo gedit /opt/local/etc/macports/macports.conf
}}}
and add:
{{{
default_compilers      clang            # compiler selection is not yet working on Ubuntu, this chooses /usr/bin/clang which works best with macport's portfiles
cxx_stdlib             libstdc++        # configure.cxx_stdlib is not yet working on Ubuntu, this fills in appropriate default
}}}

Darwin and Ubuntu supply 'sed' and 'grep' in different locations, so rather than edit many Portfiles that expect it in the Darwin location, you can do this:
{{{
sudo ln -s /bin/sed /usr/bin/sed
sudo ln -s /bin/grep /usr/bin/grep
}}}

And at that point, you should be able to run normal MacPorts commands. 
{{{
sudo port -v selfupdate
}}}
will update your ports tree to the current status.

And then try to install a typical port, like this:
{{{
sudo port -v install libffi
}}}

And presto:
{{{
$ port -v installed
The following ports are currently installed:
  libffi @3.2.1_0 (active) platform='linux 5' archs='x86_64' date='2020-05-02T23:25:44-0700
}}}

You can certainly expect to come across issues; MacPorts' PortFiles have largely been written to assume they are installing on Darwin, but with minor modifications to some ports, seem happy with Linux as well.