Trying Jekyll for the first time, I get hit by the same issue. Indeed this flag is a good start, but afterwards:
1. we have to gather we should change the Gemfile to use: source "file:///usr/lib/ruby/vendor_ruby" 2. we get hit by missing bundles, that should surely be added as Recommends: (and it is a bit painful, as I'm testing using "bundle outdated" which only complains one missing package at a time). I could install the following: * jekyll-theme-minima * ruby-tzinfo But then the following gem is missing, and apparently not available in Debian: * tzinfo-data I tried to remove it from the Gemfile, and the next problem is: Could not find gem 'jekyll (~> 3.8.6)' in any of the gem sources listed in your Gemfile. ... which is quite unfortunate, as obviously the Debian package is installed. So it seems we cannot make use of full-local gems yet. But back to the https source, the install also fails to complete: $ bundle install --path vendor/bundle [DEPRECATED] The `--path` flag is deprecated because it relies on being remembered across bundler invocations, which bundler will no longer do in future versions. Instead please use `bundle config set path 'vendor/bundle'`, and stop using this flag Fetching gem metadata from https://rubygems.org/........... Fetching gem metadata from https://rubygems.org/. Resolving dependencies... Fetching public_suffix 4.0.4 Installing public_suffix 4.0.4 Fetching addressable 2.7.0 Installing addressable 2.7.0 Using bundler 2.1.4 Fetching colorator 1.1.0 Installing colorator 1.1.0 Fetching concurrent-ruby 1.1.6 Installing concurrent-ruby 1.1.6 Fetching eventmachine 1.2.7 Installing eventmachine 1.2.7 with native extensions Gem::Ext::BuildError: ERROR: Failed to build gem native extension. current directory: /home/yann/perso/blog/bar/vendor/bundle/ruby/2.7.0/gems/eventmachine-1.2.7/ext /usr/bin/ruby2.7 -I /usr/lib/ruby/2.7.0 -r ./siteconf20200419-2300959-b7mzat.rb extconf.rb mkmf.rb can't find header files for ruby at /usr/lib/ruby/include/ruby.h You might have to install separate package for the ruby development environment, ruby-dev or ruby-devel for example. extconf failed, exit code 1 Gem files will remain installed in /home/yann/perso/blog/bar/vendor/bundle/ruby/2.7.0/gems/eventmachine-1.2.7 for inspection. Results logged to /home/yann/perso/blog/bar/vendor/bundle/ruby/2.7.0/extensions/x86_64-linux/2.7.0/eventmachine-1.2.7/gem_make.out An error occurred while installing eventmachine (1.2.7), and Bundler cannot continue. Make sure that `gem install eventmachine -v '1.2.7' --source 'https://rubygems.org/'` succeeds before bundling. In Gemfile: minima was resolved to 2.5.1, which depends on jekyll-feed was resolved to 0.13.0, which depends on jekyll was resolved to 3.8.6, which depends on em-websocket was resolved to 0.5.1, which depends on eventmachine Now it I want to take the hint and use `gem install eventmachine -v '1.2.7' --source 'https://rubygems.org/'`, after following the recommendation to do `bundle config set path 'vendor/bundle'`, that just seems to ignore the setting: $ gem install eventmachine -v '1.2.7' --source 'https://rubygems.org/' ERROR: While executing gem ... (Gem::FilePermissionError) You don't have write permissions for the /var/lib/gems/2.7.0 directory. ... and it looks like `--source` and `--path` are incompatible anyway, if I use both, whatever the order, the second option is reported as "Unknown switches" Being quite a stranger to ruby things (which is usually a good starting point for validating a user documentation ;), all this is extremely confusing :) For a start, you could include a step-by-step instruction sheet to make use of jekyll in Debian. Best regards, -- Yann
