Say you want to use Coq master, but you want to install it in a way which does not interfere with your existing Coq installation(s).
Here's one way to do this:
First, install opam (these instructions were tested with opam 2.0.3).
Start by running
opam update
to fetch the latest package metadata.
Then, run
opam switch list-available
to list the available OCaml versions, and choose an OCaml version you think will be compatible with the Coq version you're going to install.
In our example, we choose OCaml version 4.09.0, and give it the name OnlyOcaml4.09.0:
opam switch create OnlyOcaml4.09.0 4.09.0
Then run
eval $(opam env)
and after that, if ocamlc --version prints 4.09.0, OCaml should be installed correctly.
We also need these dependencies (add lablgtk3-sourceview3 if you want CoqIDE):
opam install num ocamlfind
Then cd to a directory of your choice (let's call it $MYDIR) and do
git clone [email protected]:coq/coq.git
cd coq
./configure -local
make -j4
where -j4 indicates to use 4 processor cores during compilation and can be adapted depending on your machine.
After this, in any terminal where you want to use this Coq version, run the following command:
export PATH=$MYDIR/coq/bin/:$PATH
Helpful commands to test if you indeed have to version you want:
which coqc
coqc -v