568
votes

I was trying to install rails on Ubuntu Natty Narwhal 11.04, using ruby1.9.1.

I installed ruby using apt-get install ruby1.9.1-full which contains the dev package. I googled the error and all have suggested I install the 1.9.1-dev which I already have.

Building native extensions.  This could take a while...
ERROR:  Error installing rails:
    ERROR: Failed to build gem native extension.

        /usr/bin/ruby1.8 extconf.rb
extconf.rb:36:in `require': no such file to load -- mkmf (LoadError)
    from extconf.rb:36


Gem files will remain installed in /usr/lib/ruby/gems/1.8/gems/bcrypt-ruby-3.0.1 for inspection.
Results logged to /usr/lib/ruby/gems/1.8/gems/bcrypt-ruby-3.0.1/ext/mri/gem_make.out
10
I had a parallel error attempting to install watir-webdriver. It also was corrected by installing ruby1.0.1-devkaleidic

10 Answers

980
votes

After some search for a solution it turns out the -dev package is needed, not just ruby1.8. So if you have ruby1.9.1 doing

sudo apt-get install ruby1.9.1-dev

or to install generic ruby version, use (as per @lamplightdev comment):

sudo apt-get install ruby-dev

should fix it.

Try locate mkmf to see if the file is actually there.

185
votes

This is the answer that worked for me. Was in the comments above, but deserves its rightful place as answer for ubuntu 12.04 ruby 1.8.7

sudo apt-get install ruby-dev
# if above doesnt work make sure you have build essential
sudo apt-get install build-essential
37
votes

I also needed build-essential installed:

sudo apt-get install build-essential
30
votes

The problem is still is recursive on Ubuntu 13/04/13.10/14.04

and

sudo apt-get install ruby1.9.1-dev

worked out for me okay. So If you are using Ubuntu 13.04/13.10/14.04 then using this will really come in handy.

This works even if ruby version is 1.9.3. This is because there is no ruby1.9.3-dev available in the Repository...

18
votes

Have you tried:

sudo apt-get install ruby1.8-dev
10
votes

I got the similar error when install bundle

sudo apt-get install ruby-dev

Works great for me and solve the problem Mint 16 ruby1.9.3

2
votes

I think is a little late but

sudo yum install -y gcc ruby-devel libxml2 libxml2-devel libxslt libxslt-devel

worked for me on fedora.

http://nokogiri.org/tutorials/installing_nokogiri.html

1
votes

You've Ruby 1.8 so you need to upgrade to at least 1.9 to make it working.

If so, then check How to install a specific version of a ruby gem?

If this won't help, then reinstalling ruby-dev again.

0
votes

You can use RVM(Ruby version manager) which helps in managing all versions of ruby on your machine , which is very helpful for you development (when migrating to unstable release to stable release )

or for Linux (ubuntu) go for sudo apt-get install ruby1.8-dev

then sudo gem install rails to verify it do rails -v it will show version on rails

after that you can install bundles (required gems for development)

0
votes

Ruby version: 2.7.1 gem version: 3.1.3

You need to check the extension that could not be installed, and find the reasons.

Read the mkmf.log file showed at the installation error under "To see why this extension failed to compile, please check the mkmf.log which can be found here" , perhaps there is a missing lib ( sometimes iconv ), and you must install it.

You can search the extension with your package manager(apt, yum, pacman...) too.

(Personal case) Arch Linux->nokogiri

gem install rails

Showed me:

To see why this extension failed to compile, please check the mkmf.log which can be found here: /home/user/.gem/ruby/2.7.0/extensions/x86_64-linux/2.7.0/nokogiri-1.10.9/mkmf.log

Go to: https://aur.archlinux.org/packages/ruby-nokogiri/

  1. Make sure you have all dependencies installed
  2. Make sure you have make installed
  3. git clone the package
  4. cd to package
  5. makepkg the package

Hope to help!