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Mono and OS X El Capitan

16 Oct 2015

After installing OS X El Capitan on my computer I noticed that fsharp interactive failed to start because it failed to locate mono:

/Library/Frameworks/Mono.framework/Versions/4.0.4/bin/fsharpi: line 24: exec: mono: not found

Session termination detected. Press Enter to restart.

If we look at the file at that position we find that it assumes that mono is in the path. I checked /etc/paths, and it looked correct (i.e. based on the paths file, mono should have been in the path):

mathieu$ which mono
mathieu$ ls -la /usr/local/bin/mono
lrwxr-xr-x  1 mathieu  admin  48 Sep 12 21:56 /usr/local/bin/mono -> /Library/Frameworks/Mono.framework/Commands/mono

I’ve found that there is a stackoverflow answer. I opted for a somewhat different approach and created a file in my ~/bin folder with essentially the same fix (this was before the stackoverflow answer, so it’s not exactly alike). You can find it here.

After that I changed the xamarin studio f# interactive settings so that the path is ~/Users/mathieu/bin/fsharpi~.

I’m thinking that later on I want to change the settings for fsharpi and fsharp to point to a local nuget repository (containg a paket.dependencies file) with FSharp.Compiler.Tools installed.


  • mono
  • xamarin
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