1.移除现有的Ruby

$gem sources --remove https://rubygems.org/

2.使用淘宝镜像

$gem sources -a https://ruby.taobao.org/

3.验证当前ruby版本

$gem sources -l

成功后提示：

*** CURRENT SOURCES ***

https://ruby.taobao.org/

4.开始安装cocoapods

$sudo gem install cocoapods

这时候提示：

Fetching: i18n-0.7.0.gem (100%)

Successfully installed i18n-0.7.0

Fetching: thread_safe-0.3.5.gem (100%)

Successfully installed thread_safe-0.3.5

Fetching: tzinfo-1.2.2.gem (100%)

Successfully installed tzinfo-1.2.2

Fetching: minitest-5.9.0.gem (100%)

Successfully installed minitest-5.9.0

Fetching: concurrent-ruby-1.0.2.gem (100%)

Successfully installed concurrent-ruby-1.0.2

Fetching: activesupport-5.0.0.gem (100%)

ERROR:  Error installing cocoapods:

activesupport requires Ruby version >= 2.2.2.

这个地方很坑，之前安装cocoapods一直是没有这个问题的，这里提示Ruby版本要大于或等于2.2.2

于是查看ruby版本

$ruby -v

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

果然这里就要升级Ruby版本啦

查看目前的所有ruby版本：

$rvm list known

如果提示command not found 请先安装rvm

$curl -L get.rvm.io | bash -s stable  

如果已安装会列出所有的ruby版本：

# MRI Rubies

[ruby-]1.8.6[-p420]

[ruby-]1.8.7[-head] # security released on head

[ruby-]1.9.1[-p431]

[ruby-]1.9.2[-p330]

[ruby-]1.9.3[-p551]

[ruby-]2.0.0[-p648]

[ruby-]2.1[.8]

[ruby-]2.2[.4]

[ruby-]2.3[.0]

[ruby-]2.2-head

ruby-head

# for forks use: rvm install ruby-head-<name> --url https://github.com/github/ruby.Git --branch 2.2

# JRuby

jruby-1.6[.8]

jruby-1.7[.23]

jruby[-9.0.5.0]

jruby-head

# Rubinius

rbx-1[.4.3]

rbx-2.3[.0]

rbx-2.4[.1]

rbx[-2.5.8]

rbx-head

# Opal

opal

# Minimalistic ruby implementation - ISO 30170:2012

mruby[-head]

# Ruby Enterprise Edition

ree-1.8.6

ree[-1.8.7][-2012.02]

# GoRuby

goruby

# Topaz

topaz

# MagLev

maglev[-head]

maglev-1.0.0

# Mac OS X Snow Leopard Or Newer

macruby-0.10

macruby-0.11

macruby[-0.12]

macruby-nightly

macruby-head

# IronRuby

ironruby[-1.1.3]

ironruby-head

这里我们安装2.2.2:

$rvm install 2.2.2

终端运行结果：（如果直接成功请绕过homebrew的卸载安装）

Searching for binary rubies, this might take some time.

Found remote file https://rvm_io.global.ssl.fastly.net/binaries/osx/10.11/x86_64/ruby-2.2.2.tar.bz2

Checking requirements for osx.

About to install Homebrew, press `Enter` for default installation in `/usr/local`,

type new path if you wish custom Homebrew installation (the path needs to be writable for user)

: 

回车：

It appears Homebrew is already installed. If your intent is to reinstall you

should do the following before running this installer again:

    ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"

The current contents of /usr/local are .git

Requirements installation failed with status: 1.

这里执行：

$ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"

卸载home-brew

Warning: This script will remove:

/Library/Caches/Homebrew/

/usr/local/.git/

Are you sure you want to uninstall Homebrew? [y/N] y

==> Removing Homebrew installation...

==> Removing empty directories...

==> Homebrew uninstalled!

You may want to restore /usr/local's original permissions

  sudo chmod 0755 /usr/local

  sudo chgrp wheel /usr/local

再执行：

$ rvm install 2.2.2

提示：

Searching for binary rubies, this might take some time.

Found remote file https://rvm_io.global.ssl.fastly.net/binaries/osx/10.11/x86_64/ruby-2.2.2.tar.bz2

Checking requirements for osx.

About to install Homebrew, press `Enter` for default installation in `/usr/local`,

type new path if you wish custom Homebrew installation (the path needs to be writable for user)

: 

按回车：

==> This script will install:

/usr/local/bin/brew

/usr/local/Library/...

/usr/local/share/doc/homebrew

/usr/local/share/man/man1/brew.1

/usr/local/share/zsh/site-functions/_brew

/usr/local/etc/bash_completion.d/brew

Press RETURN to continue or any other key to abort

==> /usr/bin/sudo /bin/mkdir /Library/Caches/Homebrew

这里需要输入电脑密码：

==> /usr/bin/sudo /bin/chmod g+rwx /Library/Caches/Homebrew

==> /usr/bin/sudo /usr/sbin/chown haha /Library/Caches/Homebrew

==> Downloading and installing Homebrew...

remote: Counting objects: 501, done.

remote: Compressing objects: 100% (445/445), done.

remote: Total 501 (delta 29), reused 360 (delta 27), pack-reused 0

Receiving objects: 100% (501/501), 787.83 KiB | 169.00 KiB/s, done.

Resolving deltas: 100% (29/29), done.

From https://github.com/Homebrew/brew

 * [new branch]      master     -> origin/master

HEAD is now at 32f7e73 download_strategy: ensure fixed commit hash length

==> Tapping homebrew/core

Cloning into '/usr/local/Library/Taps/homebrew/homebrew-core'...

remote: Counting objects: 3714, done.

remote: Compressing objects: 100% (3598/3598), done.

remote: Total 3714 (delta 14), reused 2112 (delta 6), pack-reused 0

Receiving objects: 100% (3714/3714), 2.88 MiB | 240.00 KiB/s, done.

Resolving deltas: 100% (14/14), done.

Checking connectivity... done.

Checking out files: 100% (3717/3717), done.

Tapped 3591 formulae (3,740 files, 9.0M)

==> Installation successful!

==> Next steps

Run `brew help` to get started

Further documentation: https://git.io/brew-docs

==> Homebrew has enabled anonymous aggregate user behaviour analytics

Read the analytics documentation (and how to opt-out) here:

  https://git.io/brew-analytics

Installing requirements for osx.

Updating system.....

Installing required packages: autoconf, automake, libtool, pkg-config, libyaml, readline, libksba, openssl........

Certificates in '/usr/local/etc/openssl/cert.pem' are already up to date.

Requirements installation successful.

ruby-2.2.2 - #configure

ruby-2.2.2 - #download

  % Total    % Received % Xferd  Average Speed   Time    Time     Time  Current

                                 Dload  Upload   Total   Spent    Left  Speed

100 6854k  100 6854k    0     0  61342      0  0:01:54  0:01:54 --:--:--  132k

ruby-2.2.2 - #validate archive

ruby-2.2.2 - #extract

ruby-2.2.2 - #validate binary

ruby-2.2.2 - #setup

ruby-2.2.2 - #gemset created /Users/haha/.rvm/gems/ruby-2.2.2@global

ruby-2.2.2 - #importing gemset /Users/haha/.rvm/gemsets/global.gems..............................

ruby-2.2.2 - #generating global wrappers........

ruby-2.2.2 - #gemset created /Users/haha/.rvm/gems/ruby-2.2.2

ruby-2.2.2 - #importing gemsetfile /Users/haha/.rvm/gemsets/default.gems evaluated to empty gem list

ruby-2.2.2 - #generating default wrappers........

Updating certificates in '/etc/openssl/cert.pem'.

mkdir: /etc/openssl: Permission denied

mkdir -p "/etc/openssl" failed, retrying with sudo

haha password required for 'mkdir -p /etc/openssl': 

and sudo mkdir worked

这样ruby2.2.2就安装好了

现在就可以安装cocoapods啦：

$sudo gem install cocoapods

看看这样cocoapods就安装成功了

Fetching: nap-1.1.0.gem (100%)

Successfully installed nap-1.1.0

Fetching: fourflusher-0.3.2.gem (100%)

Successfully installed fourflusher-0.3.2

Fetching: escape-0.0.4.gem (100%)

Successfully installed escape-0.0.4

Fetching: colored-1.2.gem (100%)

Successfully installed colored-1.2

Fetching: concurrent-ruby-1.0.2.gem (100%)

Successfully installed concurrent-ruby-1.0.2

Fetching: thread_safe-0.3.5.gem (100%)

Successfully installed thread_safe-0.3.5

Fetching: tzinfo-1.2.2.gem (100%)

Successfully installed tzinfo-1.2.2

Fetching: i18n-0.7.0.gem (100%)

Successfully installed i18n-0.7.0

Fetching: activesupport-5.0.0.gem (100%)

Successfully installed activesupport-5.0.0

Fetching: claide-1.0.0.gem (100%)

Successfully installed claide-1.0.0

Fetching: xcodeproj-1.1.0.gem (100%)

Successfully installed xcodeproj-1.1.0

Fetching: molinillo-0.4.5.gem (100%)

Successfully installed molinillo-0.4.5

Fetching: cocoapods-try-1.0.0.gem (100%)

Successfully installed cocoapods-try-1.0.0

Fetching: netrc-0.7.8.gem (100%)

Successfully installed netrc-0.7.8

Fetching: cocoapods-trunk-1.0.0.gem (100%)

Successfully installed cocoapods-trunk-1.0.0

Fetching: cocoapods-stats-1.0.0.gem (100%)

Successfully installed cocoapods-stats-1.0.0

Fetching: cocoapods-search-1.0.0.gem (100%)

Successfully installed cocoapods-search-1.0.0

Fetching: cocoapods-plugins-1.0.0.gem (100%)

Successfully installed cocoapods-plugins-1.0.0

Fetching: cocoapods-downloader-1.0.1.gem (100%)

Successfully installed cocoapods-downloader-1.0.1

Fetching: cocoapods-deintegrate-1.0.0.gem (100%)

Successfully installed cocoapods-deintegrate-1.0.0

Fetching: fuzzy_match-2.0.4.gem (100%)

Successfully installed fuzzy_match-2.0.4

Fetching: cocoapods-core-1.0.1.gem (100%)

Successfully installed cocoapods-core-1.0.1

Fetching: cocoapods-1.0.1.gem (100%)

Successfully installed cocoapods-1.0.1

Parsing documentation for nap-1.1.0

Installing ri documentation for nap-1.1.0

Parsing documentation for fourflusher-0.3.2

Installing ri documentation for fourflusher-0.3.2

Parsing documentation for escape-0.0.4

Installing ri documentation for escape-0.0.4

Parsing documentation for colored-1.2

Installing ri documentation for colored-1.2

Parsing documentation for concurrent-ruby-1.0.2

Installing ri documentation for concurrent-ruby-1.0.2

Parsing documentation for thread_safe-0.3.5

Installing ri documentation for thread_safe-0.3.5

Parsing documentation for tzinfo-1.2.2

Installing ri documentation for tzinfo-1.2.2

Parsing documentation for i18n-0.7.0

Installing ri documentation for i18n-0.7.0

Parsing documentation for activesupport-5.0.0

Installing ri documentation for activesupport-5.0.0

Parsing documentation for claide-1.0.0

Installing ri documentation for claide-1.0.0

Parsing documentation for xcodeproj-1.1.0

Installing ri documentation for xcodeproj-1.1.0

Parsing documentation for molinillo-0.4.5

Installing ri documentation for molinillo-0.4.5

Parsing documentation for cocoapods-try-1.0.0

Installing ri documentation for cocoapods-try-1.0.0

Parsing documentation for netrc-0.7.8

Installing ri documentation for netrc-0.7.8

Parsing documentation for cocoapods-trunk-1.0.0

Installing ri documentation for cocoapods-trunk-1.0.0

Parsing documentation for cocoapods-stats-1.0.0

Installing ri documentation for cocoapods-stats-1.0.0

Parsing documentation for cocoapods-search-1.0.0

Installing ri documentation for cocoapods-search-1.0.0

Parsing documentation for cocoapods-plugins-1.0.0

Installing ri documentation for cocoapods-plugins-1.0.0

Parsing documentation for cocoapods-downloader-1.0.1

Installing ri documentation for cocoapods-downloader-1.0.1

Parsing documentation for cocoapods-deintegrate-1.0.0

Installing ri documentation for cocoapods-deintegrate-1.0.0

Parsing documentation for fuzzy_match-2.0.4

Installing ri documentation for fuzzy_match-2.0.4

Parsing documentation for cocoapods-core-1.0.1

Installing ri documentation for cocoapods-core-1.0.1

Parsing documentation for cocoapods-1.0.1

Installing ri documentation for cocoapods-1.0.1

Done installing documentation for nap, fourflusher, escape, colored, concurrent-ruby, thread_safe, tzinfo, i18n, activesupport, claide, xcodeproj, molinillo, cocoapods-try, netrc, cocoapods-trunk, cocoapods-stats, cocoapods-search, cocoapods-plugins, cocoapods-downloader, cocoapods-deintegrate, fuzzy_match, cocoapods-core, cocoapods after 146 seconds

23 gems installed