Posting this for future reference. If you are on Fedora 30 and attempting to use esy, you might get a message like this:
error unable to fetch @esy-ocaml/substs@0.0.1:
source: archive:https://registry.npmjs.org/@esy-ocaml/substs/-/substs-0.0.1.tgz#sha1:59ebdbbaedcda123fc7ed8fb2b302b7d819e9a46
error: error: run ['shasum' '--algorithm' '1'
That problem is that Fedora doesn’t automatically have shasum installed. Install it via:
sudo dnf install perl-Digest-SHA