Install Unison 2.51.2 on Debian / Ubuntu - Used in Vagrant Guest Machines for compatibility with OSX Unison version

unison.sh

#!/bin/bash

apt-get update
apt-get install libdpkg-perl -y -f --allow-downgrades
apt-get install ocaml ocaml-native-compilers camlp4-extra opam -y -f

mkdir -p /usr/src/unison/
cd /usr/src/unison/

wget https://github.com/bcpierce00/unison/archive/refs/tags/v2.51.2.tar.gz -O unison.tar.gz
tar xzvf unison.tar.gz  --strip-components 1
make UISTYLE=text || true

chmod +x unison unison-*
rm /usr/bin/unison
rm /usr/bin/unison-*

ln -s $PWD/unison /usr/bin/
ln -s $PWD/unison-* /usr/bin/

echo "fs.inotify.max_user_watches=262144" > /etc/sysctl.d/90-unison-notify.conf
sysctl -p --system

this is very helpful, thank you! however, for unison to work properly, both client and server must not only have the same unison version installed, but it also needs to be compiled with the same version of OCaml on both ends. this is quite frustrating, as the ubuntu package manager currently only delivers OCaml 4.05.0, and my client runs unison version 2.51.2 (ocaml 4.08.1). how would you extend your script to install unison 2.51.2 on debian/ubuntu, but using the latest OCaml version 4.08.1? alternatively, any tipps on manual installation of OCaml 4.08.1 on ubuntu would be much appreciated as well. thank you!

UPDATE for whom might be interested: I installed OCaml 4.08.1 from source, but the unison source code wouldn't compile if downloaded and extracted from https://www.seas.upenn.edu/~bcpierce/unison/download/releases/unison-2.51.2/unison-2.51.2.tar.gz. I ended up cloning unison from the official git repository https://github.com/bcpierce00/unison/ and then the installation went without a problem.

find instructions here: https://github.com/markbil/linux-insights/blob/master/unison_ocaml_installFromSource.md

thanks for the inspiration @dasginganinja.

Thanks for the update on that @markbil! I found that my instructions stopped working at one point and I went back to using polling-based watching because the fsmonitor was broken.

I'll take a look at your instructions. I'm going to match whatever version of ocaml the unison installed via brew has on the server side.

Here was the fix that I put in place (adapted from code from @markbil)

I ended up going with 4.07.0 since that is the current version returned by unison -version -- unison version 2.51.2 (ocaml 4.07.0).

4.07.1 ended up erroring out when make tags was ran by the unison Makefile.

  # Remove current references of oCaml
  apt purge ocaml
  rm -r /usr/bin/ocaml*

  # Remove current versions of unison binaries
  apt purge unison
  rm -r /usr/bin/unison
  rm -r /usr/bin/unison-*

  # Compile OCaml from source
  mkdir -p /usr/src/ocaml
  cd /usr/src/ocaml
  wget http://caml.inria.fr/pub/distrib/ocaml-4.07/ocaml-4.07.0.tar.gz
  tar xzvf ocaml-4.07.0.tar.gz --strip-components 1
  ./configure
  make world.opt
  make install
  make clean

  # Compile Unison from source
  rm -rf /usr/src/unison/
  mkdir -p /usr/src/unison/
  cd /usr/src/unison/
  wget https://www.seas.upenn.edu/~bcpierce/unison/download/releases/unison-2.51.2/unison-2.51.2.tar.gz -O unison.tar.gz
  tar xzvf unison.tar.gz  --strip-components 1
  make UISTYLE=text || true

  chmod +x unison unison-*
  ln -s $PWD/unison /usr/bin/
  ln -s $PWD/unison-* /usr/bin/

  unison -version

I'm sure I'll need to update the original install script at some point in the near future so I'll get a new revision in then. ;)

Change the archive link
https://github.com/bcpierce00/unison/archive/refs/tags/v2.51.2.tar.gz

@Wedmal Thank you -- updated.