How to use Eclipse with an existing sbt project

Assuming there is a sbt project, and now you want to use Eclipse to maintain the project.

(1) Install sbteclipse plugin in your sbt project to generate Eclipse project configs
You should follow the instruction on (use "sbt sbtVersion" to get your sbt version):
https://github.com/typesafehub/sbteclipse
but I did not manage to install the sbteclipse plugin globally for any sbt project, so I had to install it per project, i.e., adding

addSbtPlugin("com.typesafe.sbteclipse" % "sbteclipse-plugin" % "4.0.0")

to PROJECT_DIR/project/plugins.sbt in your sbt project.
After sbteclipse is installed, you could run:

sudo sbt eclipse

to generate project config files for Eclipse:

    .classpath
    .project
    .settings/

(2) Import the project into Eclipse
Use menu:

File → Import → Existing Projects into Workspace

(3) How to use it
On the command line, you should run:
sudo sbt ~compile
in the root directory of your sbt project such that sbt could automatically run when you make any changes.