如何告诉bundle install在PATH上使用Ruby版本？

Question

我正在尝试在Debian上安装我的Rails 5项目。 运行带有或不带有sudo bundle install导致一个错误，抱怨没有合适的Ruby版本，即使我之后运行ruby -v ，也可以看到版本为2.4。 如何将bundle install指向正确的版本？

$ sudo bundle install
[sudo] password for myuser:
Don't run Bundler as root. Bundler can ask for sudo if it is needed, and installing your bundle as root will break this application for all non-root users on this machine.
Your Gemfile lists the gem jquery-rails (>= 0) more than once.
You should probably keep only one of them.
While it's not a problem now, it could cause errors if you change the version of just one of them later.
Fetching gem metadata from https://rubygems.org/........
Fetching additional metadata from https://rubygems.org/..
Using rake 12.0.0
Using concurrent-ruby 1.0.5
Using i18n 0.8.6
Using minitest 5.10.3
Using thread_safe 0.3.6
Using tzinfo 1.2.3

Gem::InstallError: activesupport requires Ruby version >= 2.2.2.
An error occurred while installing activesupport (5.0.4), and Bundler cannot continue.
Make sure that `gem install activesupport -v '5.0.4'` succeeds before bundling.

$ ruby -v
ruby 2.4.0p0 (2016-12-24 revision 57164) [armv6l-linux-eabihf]

没有sudo运行：

$ bundle install
Your Gemfile lists the gem jquery-rails (>= 0) more than once.
You should probably keep only one of them.
While it's not a problem now, it could cause errors if you change the version of just one of them later.
Fetching gem metadata from https://rubygems.org/........
Fetching additional metadata from https://rubygems.org/..
Using rake 12.0.0
Using concurrent-ruby 1.0.5
Using i18n 0.8.6
Using minitest 5.10.3
Using thread_safe 0.3.6
Using tzinfo 1.2.3

Gem::InstallError: activesupport requires Ruby version >= 2.2.2.
An error occurred while installing activesupport (5.0.4), and Bundler cannot continue.
Make sure that `gem install activesupport -v '5.0.4'` succeeds before bundling.

$ ruby -v
ruby 2.4.0p0 (2016-12-24 revision 57164) [armv6l-linux-eabihf]

Answer 1

调用捆绑软件时，首先， bundle本身会在$PATH得到解析。 您可以通过键入whereis bundle或which bundle检查其可执行文件所在的位置。 就我而言（Ubuntu 16.04），它位于/usr/local/bin/bundle 。

如果执行cat /usr/local/bin/bundle ，我们将获得此可执行文件的内容：

$ cat /usr/local/bin/bundle
#!/usr/bin/ruby2.4
#
# This file was generated by RubyGems.
#
# The application 'bundler' is installed as part of a gem, and
# this file is here to facilitate running it.
#

require 'rubygems'

version = ">= 0.a"

if ARGV.first
  str = ARGV.first
  str = str.dup.force_encoding("BINARY") if str.respond_to? :force_encoding
  if str =~ /\A_(.*)_\z/ and Gem::Version.correct?($1) then
    version = $1
    ARGV.shift
  end
end

load Gem.activate_bin_path('bundler', 'bundle', version)

如您所见，这是一个简单的Ruby脚本，最上面的行（ #!/usr/bin/ruby2.4 ）设置解释器来执行它。

我想，在您的情况下，使用的是旧版本的Ruby，因为如果在安装2.4.0之前您的系统中装有Ruby， gem可执行文件就不会更新为2.4，并且还使用旧的Ruby版本。 您可以通过执行which gem （对我来说是/usr/bin/gem ）并使用cat检查文件内容来进行检查。

之后，您可以通过键入whereis gem来检查gem的可用可执行文件：

$ whereis gem
gem: /usr/bin/gem /usr/bin/gem2.2 /usr/bin/gem2.4

然后，您可以通过输入gem uninstall bundler来删除捆绑器（这也将删除其可执行文件），然后使用正确的gem重新安装它，执行：

/usr/bin/gem2.4 install bundle

这应该可以解决问题，因为在Bundle的可执行文件中，您将获得Ruby 2.4作为解释器。

update-alternatives命令在这种情况下也很有用。

如您所见，这令人头疼，所以我的建议是使用Ruby版本管理器（ rvm ， rbenv等），或者每台计算机仅使用一个Ruby版本。

Answer 2

gem install rails --version 5.0.0