# gem install redis-dump
Fetching: yajl-ruby-1.3.1.gem (100%)
Building native extensions. This could take a while...
ERROR: Error installing redis-dump:
ERROR: Failed to build gem native extension.
current directory: /var/lib/gems/2.3.0/gems/yajl-ruby-1.3.1/ext/yajl
/usr/bin/ruby2.3 -r ./siteconf20180302-17663-4bv1w.rb extconf.rb
mkmf.rb can't find header files for ruby at /usr/lib/ruby/include/ruby.h
extconf failed, exit code 1
Gem files will remain installed in /var/lib/gems/2.3.0/gems/yajl-ruby-1.3.1 for inspection.
Results logged to /var/lib/gems/2.3.0/extensions/x86_64-linux/2.3.0/yajl-ruby-1.3.1/gem_make.out