Can't preview markdown format on Ubuntu Linux

[iryston]

Hi!
The error occurs with this plugin on Linux:

Preview: To preview markdown format you need to install redcarpet gem
Press ENTER or type command to continue

$ which redcarpet
/usr/local/bin/redcarpet
$ echo $PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/usr/local/games

The same configuration on my OS X machine with this plugin works as expected.

[greyblake]

Hi!
Do you have redcarpet gem installed (not executable).
Can you execute:

$ gem list | grep redcarpet

If you don't see it, you have install it with command:

gem install redcarpet

[iryston]

I have redcarpet installed

$ gem list | grep redcarpet
redcarpet (3.3.4)

it is installed in /usr/local/bin/ and is available in my $PATH

[brunodd]

Same issue here. (I have same redcarpet version installed). I'm running OS X El Capitan

[iryston]

It's strange, because I use this Vim configuration (https://github.com/iryston/vim-wd) on both Xubuntu 14.04 and OS X El Capitan, and everything works fine in OS X.

[greyblake]

Could you please save the next file:

ruby <<RUBY_CODE
    puts RUBY_DESCRIPTION
    require 'rubygems'
    require 'redcarpet'
RUBY_CODE

And then type in your Vim keeping the file opened :so %
What output do you get?

[brunodd]

I get:
line 6: LoadError: cannot load such file -- redcarpet

However, if I run
redcarpet --version
in Terminal, I get output:
Redcarpet 3.3.4%

[brunodd]

UPDATE:
After saving the file

require 'redcarpet'
renderer = Redcarpet::Render::HTML
markdown = Redcarpet::Markdown.new(renderer)
text = '# THIS IS TITLE'
p markdown.render text

and running it, I get the expected output:
"\<h1>THIS IS TITLE\</h1>\n"

UPDATE 2:
When I run the original file from the terminal, output is correct:
ruby 2.3.0p0 (2015-12-25 revision 53290) [x86_64-darwin15]

[iryston]

On OS X
ruby 2.0.0p645 (2015-04-13 revision 50299) [universal.x86_64-darwin15]

On Linux

ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
Error detected while processing /tmp/test.rb:
line    5:
LoadError: cannot load such file -- redcarpet

[greyblake]

@iryston , @brunodd Thanks guys.
Looks like your Vims were compiled with ruby 1.9, but in your terminal you are using 2.3. I am not 100% sure, but this may cause the issue.

Also, do you guys use rvm or rbenv? Can you make sure that, when you run Vim redcarpet is accessible?

$ gem list | grep redcarpet  # make sure the gem is present
$vim                         # run vim
# Try to execute same ruby code in vim or preview markdown

[brunodd]

@greyblake
My Vim was compiled with ruby 2.0: when I run your script from within Vim I get

ruby 2.0.0p645 (2015-04-13 revision 50299) [universal.x86_64-darwin15]
Error detected while processing /Users/brunodd/test.rb:
line    6:
LoadError: cannot load such file -- redcarpet

[iryston]

@greyblake Thank you! My Vim is compiled with ruby 1.9 (default ubuntu package). I use rbenv.

$ rbenv global 1.9.3-p484
$ ruby -v
> ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
$ gem list | grep redcarpet
redcarpet (3.3.4)
$ vim /tmp/test.rb
:ruby puts RUBY_DESCRIPTION
> ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
# Try to execute same ruby code
:so %
> ruby 1.9.3p484 (2013-11-22 revision 43786) [x86_64-linux]
> Error detected while processing /tmp/test.rb:
> line    5:
> LoadError: cannot load such file -- redcarpet

[iryston]

@brunodd
My Vim in OS X was compiled with ruby 2.0 too.

$ ruby -v
ruby 2.0.0p645 (2015-04-13 revision 50299) [universal.x86_64-darwin15]

$ gem list | grep redcarpet
redcarpet (3.3.4)

$ vim
:ruby puts RUBY_DESCRIPTION
ruby 2.0.0p645 (2015-04-13 revision 50299) [universal.x86_64-darwin15]

And everything works fine.

[brunodd]

Those commands all give the exact same output on my machine. But when running the script from within vim using
:so %
I get the:

line    6:
LoadError: cannot load such file -- redcarpet

Error

[iryston]

One more strange thing.
In linux terminal:

$ wget https://raw.githubusercontent.com/greyblake/vim-preview/master/README.markdown -O /tmp/README.html; \
vim /tmp/README.html

In Vim:

:%!redcarpet
:exe ':silent !firefox %'

And it works!

But if I do it with plugin:

$ wget https://raw.githubusercontent.com/greyblake/vim-preview/master/README.markdown -O /tmp/README.markdown; \
vim /tmp/README.markdown

In Vim:

:PreviewMarkdown

There is an error
Preview: To preview markdown format you need to install redcarpet gem