如何查看是否安装了 passenger gem

How do I see if the passenger gem is installed

不确定为什么会这样?我正在尝试获得一个 ruby 应用程序,我通过 Apache 在端口 80 上工作,但我遇到了每一个障碍:)

root../public/htdocs# bundle show passenger
Could not find gem 'passenger'.
Did you mean passenger?
root../public/htdocs# gem install passenger
Building native extensions.  This could take a while...
Successfully installed passenger-5.0.21
1 gem installed
Installing ri documentation for passenger-5.0.21...
Installing RDoc documentation for passenger-5.0.21...
root../public/htdocs# bundle show passenger
Could not find gem 'passenger'.
Did you mean passenger?

您没有提供关于 OS 的背景信息,您是 运行ning,您用来管理 Ruby、gem 的不同版本的包管理器 e.g "rbenv , rvm ....etc" 您如何管理您的 gems .. e.g locally , globally , via gemset... etc 。所以,一般来说,您可以使用 运行 gem list 和 grep 获取 gem 的名称,如下所示,以 gem 限定符为例:

user@user-SVE1411EGXB:~/shop_app/depot2$ gem list | grep uglif*
uglifier (2.7.2, 2.6.0, 2.5.3, 2.5.1, 2.5.0, 2.4.0, 1.2.7, 1.2.4)

或者您可以通过将 gem 的名称作为 ARG 传递给 gem list

来指定
user@user-SVE1411EGXB:~/shop_app/depot2$ gem list uglifier

*** LOCAL GEMS ***

uglifier (2.7.2, 2.6.0, 2.5.3, 2.5.1, 2.5.0, 2.4.0, 1.2.7, 1.2.4)
user@user-SVE1411EGXB:~/shop_app/depot2$