你可以使用:gem install cocoapods——pre——user

你需要修正你的路径。

要确定此修复是否有效，请运行以下命令:

which gem

这应该会输出一个你没有权限的目录:

/usr/bin/gem

要修复此问题，请执行以下步骤:

Determine the path you need to copy to your profile: rbenv init - The first line of the output is the line you need to copy over to your profile: export PATH="/Users/justin/.rbenv/shims:${PATH}" #path that needs to be copied source "/usr/local/Cellar/rbenv/0.4.0/libexec/../completions/rbenv.zsh" rbenv rehash 2>/dev/null rbenv() { typeset command command="$1" if [ "$#" -gt 0 ]; then shift fi case "$command" in rehash|shell) eval `rbenv "sh-$command" "$@"`;; *) command rbenv "$command" "$@";; esac } Copy the path to your profile and save it. Reload your profile (source ~/.zshenv for me). Run rbenv rehash.

现在当你运行哪个gem时，你应该得到一个你有权限的本地路径:

/Users/justin/.rbenv/shims/gem

你没有写/Library/Ruby/Gems/1.8目录的权限。

也就是说，你没有权限在那里写东西。

这是苹果安装的Ruby版本，供他们自己使用。虽然如果您知道自己在做什么，可以对其进行一些小的修改，因为您不确定权限问题，但我认为继续这样做并不是个好主意。

相反，我强烈建议您考虑使用rbenv或RVM来管理一个单独的Ruby，将其安装到您的主目录中的沙箱中，这样您就可以修改/折叠/主轴/更改，而不必担心会弄乱系统Ruby。

在这两者之间，我使用rbenv，尽管我过去经常使用RVM。rbenv采用了一种更加“不干涉”的方法来管理Ruby安装。RVM有很多特性并且非常强大，但是，结果是更具有侵入性。无论哪种情况，在开始安装之前，都要多阅读几次安装文档。

该错误的原因是您没有以root用户登录终端。

如果你已经在终端类型的mac上启用了根用户

$ su

如果您没有root用户，您需要使用以下步骤启用它

From the Apple menu choose System Preferences…. From the View menu choose Users & Groups. Click the lock and authenticate as an administrator account. Click Login Options…. Click the “Edit…” or “Join…” button at the bottom right. Click the “Open Directory Utility…” button. Click the lock in the Directory Utility window. Enter an administrator account name and password, then click OK. Choose Enable Root User from the Edit menu. Enter the root password you wish to use in both the Password and Verify fields, then click OK.

更多内容请登录http://support.apple.com/kb/ht1528

在被困了几个小时后，至少它对我有用。

有两种路由:使用rbenv或RVM。下面是这两种食物的食谱。在此之前，您可能希望关闭gem本地文档的安装。

echo "gem: --no-ri --no-rdoc" >> ~/.gemrc

然后:

安装rbenv

安装ruby-build

运行:

rbenv install 2.1.2 (or whatever version you prefer)
rbenv global 2.1.2
gem update --system

这将在本地目录中安装gem系统的最新版本。这意味着您不会干扰系统配置。如果您正在问这个问题，那么您不应该破坏系统安全性，并且您将花费更长的时间来了解可能遇到的问题，而不仅仅是找到一种简单的方法来避免您开始时遇到的问题。了解更多关于操作系统和编程的知识后，再学习InfoSec。

使用'RVM'替代:

rvm install 2.1.2
rvm use 2.1.2
gem update --system

这有同样的结果，您最终得到的是一个本地Ruby和Gem系统，它不会影响系统版本。不需要Homebrew，也不需要覆盖系统库等等。

正如bobbdelsol所指出的，rehash对我来说很管用:

==> which ruby
/usr/bin/ruby

==> rbenv install 1.9.3-p551
Downloading ruby-1.9.3-p551.tar.bz2...
-> https://cache.ruby-lang.org/pub/ruby/1.9/ruby-1.9.3-p551.tar.bz2
Installing ruby-1.9.3-p551...
Installed ruby-1.9.3-p551 to /Users/username/.rbenv/versions/1.9.3-p551


==> which ruby
/Users/username/.rbenv/shims/ruby

==> which gem
/Users/username/.rbenv/shims/gem

==> gem install compass
ERROR:  While executing gem ... (Gem::FilePermissionError)
    You don't have write permissions for the /Library/Ruby/Gems/2.0.0 directory.


==> ruby -v
ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin15]


==> rbenv global 1.9.3-p551


==> ruby -v
ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin15]


==> rbenv global 1.9.3-p551


==> rbenv rehash


==> ruby -v
ruby 1.9.3p551 (2014-11-13 revision 48407) [x86_64-darwin15.4.0]


==> gem install compass
Fetching: sass-3.4.22.gem (100%)
Fetching: multi_json-1.11.3.gem (100%)
Fetching: compass-core-1.0.3.gem (100%)
Fetching: compass-import-once-1.0.5.gem (100%)
Fetching: chunky_png-1.3.5.gem (100%)
Fetching: rb-fsevent-0.9.7.gem (100%)
Fetching: ffi-1.9.10.gem (100%)
Building native extensions.  This could take a while...
Fetching: rb-inotify-0.9.7.gem (100%)
Fetching: compass-1.0.3.gem (100%)
    Compass is charityware. If you love it, please donate on our behalf at http://umdf.org/compass Thanks!
Successfully installed sass-3.4.22
Successfully installed multi_json-1.11.3
Successfully installed compass-core-1.0.3
Successfully installed compass-import-once-1.0.5
Successfully installed chunky_png-1.3.5
Successfully installed rb-fsevent-0.9.7
Successfully installed ffi-1.9.10
Successfully installed rb-inotify-0.9.7
Successfully installed compass-1.0.3
9 gems installed
Installing ri documentation for sass-3.4.22...
Installing ri documentation for multi_json-1.11.3...
Installing ri documentation for compass-core-1.0.3...
Installing ri documentation for compass-import-once-1.0.5...
Installing ri documentation for chunky_png-1.3.5...
Installing ri documentation for rb-fsevent-0.9.7...
Installing ri documentation for ffi-1.9.10...
Installing ri documentation for rb-inotify-0.9.7...
Installing ri documentation for compass-1.0.3...
Installing RDoc documentation for sass-3.4.22...
Installing RDoc documentation for multi_json-1.11.3...
Installing RDoc documentation for compass-core-1.0.3...
Installing RDoc documentation for compass-import-once-1.0.5...
Installing RDoc documentation for chunky_png-1.3.5...
Installing RDoc documentation for rb-fsevent-0.9.7...
Installing RDoc documentation for ffi-1.9.10...
Installing RDoc documentation for rb-inotify-0.9.7...
Installing RDoc documentation for compass-1.0.3...