Installing Apple San Francisco Fonts on Linux

Apple has always had a knack for producing and using high-quality typography. Not too long ago, they switched the font for their UI from the classic Helvetica Neue (a typeface originating from Switzerland, known for precision watches) over to their own custom typeface, which they called San Francisco.

I like this font family so much that I’ve started using the monospaced variant for my default Terminal font. It replaced the Menlo I was using before, which is also very legible and has served me very well.

I try to use the same software and configuration on different platforms. My terminal emulator, Alacritty, is written in Rust and cross-platform. The tools I use daily, which is mostly tmux and vim for development, similarly work on all platforms. However, Linux does not have the San Francisco typeface available, out of the box, for licensing reasons.

Apple offers downloads of its San Francisco fonts for free from its developer page.

I wanted to get those fonts installed on my Linux machines as well, so that I can use exactly the same Alacritty configuration on all platforms. However, they only offer the fonts as a .dmg download, which is a disk image file and is how software is typically distributed on macOS (it’s mounted rather than uncompressed, so it behaves more like an inserted CD drive, and has the advantage that you can run Applications from mounted, compressed disk images without having to unpack them first). The question is, can I get Linux to extract this somehow? After all, Apple’s macOS is heavily UNIX-based.

$ wget -q https://developer.apple.com/design/downloads/SF-Font-Pro.dmg
$ file SF-Font-Pro.dmg
SF-Font-Pro.dmg: zlib compressed data

Interesting, so a .dmg file is just some zlib-compressed blob, similar to how a .tar.gz file is a gzip-compressed tar blob. The 7z command from the p7zip package can extract a surprising amount of archives, and it can easily extract disk image files, too.

$ 7z -oSF-Font-Pro x SF-Font-Pro.dmg
$ cd SF-Font-Pro
$ ls
SanFranciscoPro
$ ls SanFranciscoPro
'[HFS+ Private Data]'  'San Francisco Pro.pkg'

Okay, so this disk image file contains a .pkg file. The HFS+ Private Data folder can be ignored, as it is empty. What’s in the .pkg file? Let’s find out.

$ cd SanFranciscoPro
$ file 'San Francisco Pro.pkg'
San Francisco Pro.pkg: xar archive version 1, SHA-1 checksum

A XAR archive, Apple likes to use those. It’s similar to a TAR archive, but it uses XML for the table of contents. We don’t have anything on Ubuntu to unpack this natively, so we’ll have to build something. Thankfully, there’s some code up on Google Code that we can compile and use to unpack this.

$ cd ~/Downloads
$ wget -q https://storage.googleapis.com/google-code-archive-downloads/v2/code.google.com/xar/xar-1.5.2.tar.gz
$ tar xf xar-1.5.2.tar.gz
$ cd xar-1.5.2
$ ./configure
checking for gcc... gcc
...
$ make -j 4
...
$ ./src/xar --version
xar 1.5.2

After running this, we have a working build of XAR 1.5.2 in the src/ folder. We can now use this to unpack the San Francisco Pro font package.

$ mkdir unpacked && cd unpacked
$ ../../../xar-1.5.2/src/xar -x -f '../San Francisco Pro.pkg'
$ ls -l
-rwxr-xr-x 1 patrick patrick 546 Oct 28  2019 Distribution
drwxr-xr-x 1 patrick patrick  26 Jun  4 11:34 Resources
drwxr-xr-x 1 patrick patrick  42 Jun  4 11:34 SanFranciscoPro.pkg
$ ls -lh SanFranciscoPro.pkg
-rwxr-xr-x 1 patrick patrick 2.2K Oct 28  2019 Bom
-rwxr-xr-x 1 patrick patrick  287 Oct 28  2019 PackageInfo
-rwxr-xr-x 1 patrick patrick  28M Oct 28  2019 Payload

We have a few uninteresting files, but the Payload file inside the SanFranciscoPro.pkg folder is what we’re interested in, because that seems to contain some data. Let’s take a closer peek at it.

$ cd SanFranciscoPro.pkg
$ file Payload
Payload: gzip compressed data, from Unix

It’s gzip compressed data, that’s something we can handle. But what’s inside? We can find out, too.

$ gunzip < Payload | file -
/dev/stdin: ASCII cpio archive (pre-ARV4 or odc)

A CPIO archive. I’ve heard of this only from reading the POSIX standard, CPIO is similar to tar, if I understand it correctly. So we can use cpio to extract that.

$ gunzip < Payload | cpio -i
85030 blocks
$ ls
Bom  Library  PackageInfo  Payload

Extracting this has produced a Library folder. That sounds suspiciously like a macOS filesystem folder.

$ ls Library
Fonts
$ ls Library/Fonts
SF-Pro-Display-BlackItalic.otf
...

Jackpot!

All that’s left to do is to install them on the local system. This is done easily by copying them to the ~/.fonts folder and updating the font cache.

$ mkdir -p ~/.fonts/SF-Pro
$ cp Library/Fonts/*.otf ~/.fonts/SF-Pro/
$ fc-cache -vf

This should result in the fonts being available and ready to use.