I uninstalled Ruby 1.9.3 that was installed from source code, so here’s a memo of the procedure.

The list of installed files is written in .installed.list, so use this to execute rm with xargs on the files to delete them.

# cd /usr/local/src/ruby-1.9.3-p392
# cat .installed.list | xargs rm

The contents of .installed.list look like this:

# cat .installed.list
/usr/local/bin/
/usr/local/bin/ruby
/usr/local/lib/
/usr/local/lib/libruby.so.1.9.1
/usr/local/lib/libruby-static.a
/usr/local/lib/libruby.so.1.9
/usr/local/lib/libruby.so
/usr/local/lib/ruby/1.9.1/x86_64-linux/
/usr/local/lib/ruby/1.9.1/x86_64-linux/rbconfig.rb
/usr/local/lib/pkgconfig/
/usr/local/lib/pkgconfig/ruby-1.9.pc
/usr/local/bin/irb
/usr/local/bin/ri
/usr/local/bin/gem
/usr/local/bin/rdoc
/usr/local/bin/testrb
/usr/local/bin/rake
/usr/local/bin/erb
/usr/local/lib/ruby/1.9.1/
/usr/local/lib/ruby/1.9.1/net/
/usr/local/lib/ruby/1.9.1/net/smtp.rb
/usr/local/lib/ruby/1.9.1/net/ftp.rb
/usr/local/lib/ruby/1.9.1/net/pop.rb
/usr/local/lib/ruby/1.9.1/net/telnet.rb
/usr/local/lib/ruby/1.9.1/net/http.rb
/usr/local/lib/ruby/1.9.1/net/protocol.rb
/usr/local/lib/ruby/1.9.1/net/imap.rb
/usr/local/lib/ruby/1.9.1/net/https.rb
...
[truncated for brevity]

[Reference]：ソースからインストールしたRuby 1.9.1をアンインストールする方法 - mikage014の日記

That’s all from the Gemba.