no such file to load -- zlib

If you have installed rvm and then ruby and now facing below issue while installing rails-
manohar@manohar-Inspiron-1525:~$ gem install rails

ERROR:  Loading command: install (LoadError)

no such file to load -- zlib

ERROR:  While executing gem ... (NameError)
uninitialized constant Gem::Commands::InstallCommand

Below steps should fix your problem as it worked for me.

$ rvm pkg install zlib
$ rvm remove 1.9.2
$ rvm install 1.9.2 --with-zlib-dir=$rvm_path/usr


HEROKU:

If you need to use you might face below problem after installing heroku gem and running heroku commands:

no such file to load -- net/https.

Try running apt-get install libopenssl-ruby (LoadError)

Below steps will work:

$ rvm remove 1.9.2 

$ rvm pkg install openssl
$ rvm install 1.9.2 -C --with-openssl-dir=$rvm_path/usr

And to resolve both zlib and libopenssl problem use below steps:

$ rvm remove 1.9.2 

$ rvm pkg install zlib

$ rvm pkg install openssl

$ rvm install 1.9.2 -C --with-openssl-dir=$rvm_path/usr  --with-zlib-dir=$rvm_path/usr