rubygems – 无法使用RubyGem 2.7.1安装Cocoapods

>运行此bash脚本以删除所有相关的宝石：

for i in $( gem list --local --no-version | grep cocoapods );
do 
    sudo gem uninstall $i; 
done

>删除?/ .cocoapods删除podspecs的缓存：

rm -rf ~/.cocoapods/

>更新rubygem：

sudo gem update --system

>重新安装cocoapods：

sudo gem install cocoapods

然后我在步骤3和步骤4中收到文件权限拒绝错误消息：

Step3 error message:
…
…
Done installing documentation for rubygems-update after 0 seconds
Installing RubyGems 2.7.1
ERROR: While executing gem … (Errno::EPERM)
Operation not permitted @ rb_sysopen –
/System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/gem

Step4 error message:
Fetching: cocoapods-core-1.3.1.gem (100%)
Successfully installed cocoapods-core-1.3.1
Fetching: cocoapods-deintegrate-1.0.1.gem (100%)
Successfully installed cocoapods-deintegrate-1.0.1
Fetching: cocoapods-downloader-1.1.3.gem (100%)
Successfully installed cocoapods-downloader-1.1.3
Fetching: cocoapods-plugins-1.0.0.gem (100%)
Successfully installed cocoapods-plugins-1.0.0
Fetching: cocoapods-search-1.0.0.gem (100%)
Successfully installed cocoapods-search-1.0.0
Fetching: cocoapods-stats-1.0.0.gem (100%)
Successfully installed cocoapods-stats-1.0.0
Fetching: cocoapods-trunk-1.3.0.gem (100%)
Successfully installed cocoapods-trunk-1.3.0
Fetching: cocoapods-try-1.1.0.gem (100%)
Successfully installed cocoapods-try-1.1.0
ERROR: While executing gem … (Gem::FilePermissionError)
You don’t have write permissions for the /usr/bin directory.

我对Linux / OSX文件系统的了解有限,不知道出了什么问题.

以下是有关我的电脑的信息：

> OS：

macOS High Sierra 10.13.1
> Xcode：

版本9.0.1(9A1004)
我还在应用程序文件夹中将XCode 7.3.1重命名为Xcode_7
>环境路径：

echo $PATH

/Library/Frameworks/Python.framework/Versions/3.4/bin：
在/usr/local / bin目录：
在/usr/bin中：
/斌：
/usr/sbin目录：
/ sbin目录：
/选择/ X11 / bin中：
/Applications/Server.app/Contents/ServerRoot/usr/bin：
/Applications/Server.app/Contents/ServerRoot/usr/sbin
>自制软件：

brew --version

自制1.3.6
Homebrew / homebrew-core(git revision 985b; last commit 2017-11-07)

brew list

cmake libxml2忍者pkg-config readline wget
gdbm libyaml openssl python3 sqlite xz
> RubyGems：

gem --version

2.7.1

gem list

*本地宝石*
activesupport(5.1.4,4.2.10)
bigdecimal(1.3.2,默认值：1.2.8)
CFPropertyList(2.3.5,2.2.8)
claide(1.0.2)
有色2(3.1.2)
并发ruby(1.0.5)
did_you_mean(1.0.0)
逃跑(0.0.4)
fourflusher(2.0.1)
fuzzy_match(2.1.0,2.0.4)
gh_inspector(1.0.3)
i18n(0.9.1)
io-console(0.4.6,默认值：0.4.5)
json(2.1.0,默认值：1.8.3)
libxml-ruby(3.0.0,2.9.0)
mini_portile2(2.3.0)
minitest(5.10.3)
molinillo(0.6.4,0.5.7)
纳奈莫(0.2.3)
午睡(1.1.0)
net-telnet(0.1.1)
netrc(0.11.0)
nokogiri(1.5.6)
power_assert(1.1.1)
psych(2.2.4,默认值：2.1.0)
耙子(12.2.1,10.4.2)
rdoc(5.1.0,默认值：4.2.1)
ruby-macho(1.1.0)
rubygems-update(2.7.1)
sqlite3(1.3.11)
测试单元(3.2.6)
thread_safe(0.3.6)
tzinfo(1.2.4)
xcodeproj(1.5.3)