gem list -r finds nothing - ruby

Question

gem list -r ra
=> * REMOTE GEMS *
but no gems appear
gem list
=> (my installed gems)
ruby -v
=> ruby 2.5.0p0 (2017-12-25 revision 61468) [x86_64-linux]
gem -v
=> 2.7.3
gem environment
RubyGems Environment:
RUBYGEMS VERSION: 2.7.3
RUBY VERSION: 2.5.0 (2017-12-25 patchlevel 0) [x86_64-linux]
INSTALLATION DIRECTORY: /home/xxx/.gem/ruby/2.5.0
USER INSTALLATION DIRECTORY: /home/xxx/.gem/ruby/2.5.0
RUBY EXECUTABLE: /usr/local/rubies/2.5.0/bin/ruby
EXECUTABLE DIRECTORY: /home/xxx/.gem/ruby/2.5.0/bin
SPEC CACHE DIRECTORY: /home/xxx/.gem/specs
SYSTEM CONFIGURATION DIRECTORY: /usr/local/rubies/2.5.0/etc
RUBYGEMS PLATFORMS:
ruby
x86_64-linux
GEM PATHS:
/home/xxx/.gem/ruby/2.5.0
/usr/local/rubies/2.5.0/lib/ruby/gems/2.5.0
GEM CONFIGURATION:
:update_sources => true
:verbose => true
:backtrace => false
:bulk_threshold => 1000
"gem" => "--no-document"
REMOTE SOURCES:
https://rubygems.org/
SHELL PATH:
/home/xxx/.gem/ruby/2.5.0/bin
/usr/local/rubies/2.5.0/lib/ruby/gems/2.5.0/bin
/usr/local/rubies/2.5.0/bin
/home/xxx/.nvm/versions/node/v8.8.1/bin
/usr/local/heroku/bin
/home/xxx/commands
/home/xxx/bin
/usr/local/sbin
/usr/local/bin
/usr/sbin
/usr/bin
/sbin
/bin
/usr/games
/usr/local/games
/snap/bin
I haven't changed anything (that I'm aware of) in my ruby since when it did work. Any suggestions on where to look?

Answer 1

well looks like you have no sources. see in gem env "gem" => "--no-document"
try running this:
gem sources -a https://rubygems.org/
my env differs by:
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- :sources => ["https://rubygems.org/"]
- "benchmark" => false
- "gem" => "--no-rdoc --no-ri"
can you paste output of ~/.gemrc to make sure? Mine looks like:
---
:backtrace: false
:bulk_threshold: 1000
:sources:
- https://rubygems.org/
:update_sources: true
:verbose: true
benchmark: false
gem: "--no-rdoc --no-ri"
If this doesn't work, perhaps try installing ruby using rvm https://rvm.io/rvm/install