how to solve "ruby installation is missing psych" error?

I had this problem. libyaml wouldn't compile. It turns out I was missing libtool.

yum install libtool
yum install libyaml (or rvm pkg install libyaml)
rvm reinstall 1.9.3

That solved my problem.

I had the same problem (*Cent OS 5.7*), none of the above solutions worked to me.

// My console warning
/usr/local/rvm/rubies/ruby-1.9.3-p286/lib/ruby/1.9.1/yaml.rb:56:in `<top (required)>':
It seems your ruby installation is missing psych (for YAML output).
To eliminate this warning, please install libyaml and reinstall your ruby.

After doing several re-installs, I realized it's looking for yaml in ruby version of `1.9.1` instead of `1.9.3`. So i downgraded


// obviously after installing `libyaml`
rvm remove all
rvm install 1.9.1
rvm use 1.9.1 --default

And it worked 8D!

On Solaris:

# sudo crle -64 -l /usr/local/lib

to add `/usr/local/lib` to the shared library search path
(see man crle)

I built the libyaml files separately from source and installed them in /usr/local/lib. The ruby that RVM created still did not see them, and rather than muck with the makefile or the system LD_LIBRARY_PATH I just copied /usr/local/lib/libyaml* to ~/.rvm/rubies/ruby-1.9.3-p327/lib/

That quieted the warning.

On CentOS 6.3 none of the above worked. However installing **libyaml** from source *before* installing ruby resolved the problem.

$ wget

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$ tar xzvf yaml-0.1.4.tar.gz
$ cd yaml-0.1.4
$ ./configure --prefix=/usr/local
$ make
$ sudo make install

and then

rvm install 1.9.3
gem install rails

When I switch from 64 bit to 32 bit on Snow Leopard 10.6.8, I had reinstalled ruby (used rvm) to run on 32bit and met the same problem. So I just 'cleanup' all thing that cached by rvm before and problems solved. Hope this tip can help someone.

> rvm cleanup all
>
> rvm install ruby_version_here //(This way, rvm will also re-download newest yaml).

BTW, if you still meet this problem, I think you can try:

> gem install psych

This is what worked for me on Ubuntu:
- installing libyaml-dev (sudo apt-get install libyaml-dev)
- installing rvm + ruby 1.9.3

I'm using

> rvm 1.16.20 (version) by Wayne E. Seguin <[email protected]>,
> Michal Papis <[email protected]> [

[To see links please register here]

]

and also got the following error during bundle install


> .rvm/rubies/ruby-1.9.3-p194/lib/ruby/1.9.1/yaml.rb:56:in `': It seems
> your ruby installation is missing psych (for YAML output). To
> eliminate this warning, please install libyaml and reinstall your
> ruby.


Here are three different ways to resolve this error w/o having to gem install psych

1. export LD_LIBRARY_PATH=/usr/local/lib
2. alter /etc/ld.so.conf
> sudo su - root
> echo /usr/local/lib64 >> /etc/ld.so.conf
> echo /usr/local/lib >> /etc/ld.so.conf
> ldconfig

3. Fix rvm ruby 1.9.3 installation via
> patch .rvm/scripts/functions/manage/ruby < ruby-1.9.3-LDFLAGS.patch
> rvm uninstall ruby-1.9.3-p194
> export LDFLAGS='-L /usr/local/lib64 -L/usr/local/lib -Xlinker -R/usr/local/lib64 -Xlinker -R/usr/local/lib'
> rvm install ruby-1.9.3-p194 --disable-binary
> grep configure_args .rvm/src/ruby-1.9.3-p194/config.log # to confirm LDFLAG
<pre>
$ diff -c .rvm/{src/rvm/,}scripts/functions/manage/ruby
*** .rvm/src/rvm/scripts/functions/manage/ruby 2012-11-10 06:28:14.000000000 +0000
--- .rvm/scripts/functions/manage/ruby 2013-01-25 17:18:00.000000000 +0000
***************
*** 106,123 ****
# when relative is in effect libyaml is installed in ruby itself so it will be moved with ruby
prefix_path="${rvm_rubies_path}/${rvm_ruby_string}" libyaml

! __rvm_update_configure_env CFLAGS="-I${rvm_rubies_path}/${rvm_ruby_string}/include"
! __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib"
if [[ -d "${rvm_rubies_path}/${rvm_ruby_string}/lib64" ]]
! then __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib64"
fi
else
libyaml_installed || libyaml # Installs libyaml

! __rvm_update_configure_env CFLAGS="-I${rvm_path}/usr/include"
! __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib"
if [[ -d "${rvm_path}/usr/lib64" ]]
! then __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib64"
fi
fi

--- 106,123 ----
# when relative is in effect libyaml is installed in ruby itself so it will be moved with ruby
prefix_path="${rvm_rubies_path}/${rvm_ruby_string}" libyaml

! __rvm_update_configure_env CFLAGS="-I${rvm_rubies_path}/${rvm_ruby_string}/include ${CFLAGS}"
! __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib ${LDFLAGS}"
if [[ -d "${rvm_rubies_path}/${rvm_ruby_string}/lib64" ]]
! then __rvm_update_configure_env LDFLAGS="-L${rvm_rubies_path}/${rvm_ruby_string}/lib64 ${LDFLAGS}"
fi
else
libyaml_installed || libyaml # Installs libyaml

! __rvm_update_configure_env CFLAGS="-I${rvm_path}/usr/include ${CFLAGS}"
! __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib ${LDFLAGS}"
if [[ -d "${rvm_path}/usr/lib64" ]]
! then __rvm_update_configure_env LDFLAGS="-L${rvm_path}/usr/lib64 ${LDFLAGS}"
fi
fi

</pre>

For those with Mountain Lion and RVM version >= 1.18.x

RVM ships with this new tool that is used as a flag when installing ruby versions. It's called autolibs.

I got rid of this psych problem by doing the following:

`rvm reinstall ruby-1.9.3-p392 --autolibs=3`


Read the help text BEFORE by doing:

`rvm help autolibs`


Cool.

I also struggled with the same failures with `rvm install ruby-2.0.0` for many, MANY hours. I had tried all the different methods to install libyaml; `wget source`, `yum` and `rvm`. I also tried all of the different approaches listed in similar threads. Because I tried all the different methods, I had multiple installations and locations of libyaml.

RVM is perfectly capable of installing the necessary dependencies in `~/.rvm`. Simply removing the libyaml files from non-RVM install fixed this issue for me:

sudo rm /usr/local/lib/libyaml*.*

rvm reinstall ruby-2.0.0-p0

Works!