如何告訴bundle install在PATH上使用Ruby版本？

Question

我正在嘗試在Debian上安裝我的Rails 5項目。 運行帶有或不帶有sudo bundle install導致一個錯誤，抱怨沒有合適的Ruby版本，即使我之后運行ruby -v ，也可以看到版本為2.4。 如何將bundle install指向正確的版本？

$ 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]

沒有sudo運行：

$ 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

調用捆綁軟件時，首先， bundle本身會在$PATH得到解析。 您可以通過鍵入whereis bundle或which bundle檢查其可執行文件所在的位置。 就我而言（Ubuntu 16.04），它位於/usr/local/bin/bundle 。

如果執行cat /usr/local/bin/bundle ，我們將獲得此可執行文件的內容：

$ 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)

如您所見，這是一個簡單的Ruby腳本，最上面的行（ #!/usr/bin/ruby2.4 ）設置解釋器來執行它。

我想，在您的情況下，使用的是舊版本的Ruby，因為如果在安裝2.4.0之前您的系統中裝有Ruby， gem可執行文件就不會更新為2.4，並且還使用舊的Ruby版本。 您可以通過執行which gem （對我來說是/usr/bin/gem ）並使用cat檢查文件內容來進行檢查。

之后，您可以通過鍵入whereis gem來檢查gem的可用可執行文件：

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

然后，您可以通過輸入gem uninstall bundler來刪除捆綁器（這也將刪除其可執行文件），然后使用正確的gem重新安裝它，執行：

/usr/bin/gem2.4 install bundle

這應該可以解決問題，因為在Bundle的可執行文件中，您將獲得Ruby 2.4作為解釋器。

update-alternatives命令在這種情況下也很有用。

如您所見，這令人頭疼，所以我的建議是使用Ruby版本管理器（ rvm ， rbenv等），或者每台計算機僅使用一個Ruby版本。

Answer 2

gem install rails --version 5.0.0