Ruby gem show "Invalid argument" error for almost every command

[Carlos Mermingas]

I am working through NativeScript's set-up on OS X El Capitan and I am stuck at the point where I am supposed to install xcodeproj and cocoapods. Almost everything that I try to do with gemshows the same error:

$ sudo gem install xcodeproj
ERROR:  While executing gem ... (Errno::EINVAL)
    Invalid argument

The following commands show the same error, wether I run it with sudo or not:

$ gem update --system
$ gem update
$ gem install whatever
$ gem install cocoapods

I have the following versions:

$ ruby --version
ruby 2.3.1p112 (2016-04-26 revision 54768) [x86_64-darwin15]

$ gem --version
2.6.7

I've tried some of the help that I've found online, including reinstalling gem and ruby, restarting but nothing has helped.

I guess that I have a configuration problem with Ruby.

Any suggestions on how to troubleshoot this?

[Philippe Lafoucrière]

You should really try to avoid updating your system ruby.

If you want to try things, use a ruby installed by homebrew, or with rvm (or rbenv).

That will probably help :)

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