I know that you can install a specific version of a yum package using the <package name>-<version>
like this:
yum install docker-engine-1.8.2
But I'm trying to customize this using an environment variable such that if it's set, we use that version, else we use the latest. Is there some sort of pseudo-version number like "latest" that would work?
yum install docker-engine-${DOCKER_VERSION:-latest}
Obviously, using "latest" won't work, but is there something equivalent? Normally I would just use an if conditional here, but this is actually a line in a Dockerfile not a shell script, so it's rather limited in what it can do.