Fixing 'find_spec_for_exe': can't find gem bundler

When you run into following error:

'find_spec_for_exe': can't find gem bundler (>= 0.a) with executable bundle (Gem::GemNotFoundException)

It might be that your gem version is too old and does not fit bundler ~> 2.

Try updating gem:

gem update --system '2.7.9'

Useful commands when developing gems

Yank specific gem version from rubygems in all subfolders:

for d in ./cmor_*/ ; do (cd "$d" && gem yank ${PWD##*/} -v 0.0.16.pre); done