当你按现有的顺序安装cocoapods的时候
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
$sudo gem install cocoa pods
这时候会出现提示，需要你升级Ruby
使用ruby -v查看你现有的版本
结果是：ruby 2.0.0p648 (2015-12-16 revision 53162) [universal.x86_64-darwin15]
使用ruby list known查看ruby所有版本
如果提示command not found 请先安装rvm
curl -L get.rvm.io | bash -s stable（安装ram命令）
查看ruby版本后发现我们的版本确实太低了，这时候终端输入rvm install 2.2.2
如果出现这种错误：
Searching for binary rubies, this might take some time.
Found remote file https://rvm_io.global.ssl.fastly.net/binaries/osx/10.11/x86_64/ruby-2.2.2.tar.bz2
Checking requirements for osx.
Installing requirements for osx.
Updating system.........
Error running 'requirements_osx_brew_update_system ruby-2.2.2',
showing last 15 lines of /Users/chuanchunli/.rvm/log/1473597554_ruby-2.2.2/update_system.log
https://github.com/Homebrew/homebrew/wiki/Common-Issues
and make sure `brew update` works before continuing.'
++ rvm_pretty_print stderr
++ case "${rvm_pretty_print_flag:=auto}" in
++ case "${TERM:-dumb}" in
++ case "$1" in
++ [[ -t 2 ]]
++ return 1
++ printf %b 'Failed to update Homebrew, follow instructions here:
https://github.com/Homebrew/homebrew/wiki/Common-Issues
and make sure `brew update` works before continuing.\n'
Failed to update Homebrew, follow instructions here:
https://github.com/Homebrew/homebrew/wiki/Common-Issues
and make sure `brew update` works before continuing.
++ return 1
Requirements installation failed with status: 1.
不要着急，下面告诉大家怎么做，本人在这里卡了一天
终端输入
brew doctor
错误提示：
Please note that these warnings are just used to help the Homebrew maintainers
with debugging if you file an issue. If everything you use Homebrew for is
working fine: please don't worry and just ignore them. Thanks!
Warning: The following directories are not writable:
/usr/local/share/man
This can happen if you "sudo make install" software that isn't managed
by Homebrew. If a formula tries to write a file to this directory, the
install will fail during the link step.
You should change the ownership and permissions of these directories.
back to your user account.
sudo chown -R $(whoami) /usr/local/share/man
Warning: You have unlinked kegs in your Cellar
Leaving kegs unlinked can lead to build-trouble and cause brews that depend on
those kegs to fail to run properly once built. Run `brew link` on these:
autoconf
libgpg-error
libtool
pig-config
在输入：
sudo chown -R $(whoami) /usr/local/share/man
然后输入
brew link autoconf
brew link libgpg-error
brew link libtool
brew link pig-config
最后再次输入rvm install 2.2.2
这回就应该可以安装cocoapods了
安装cocoa pods命令：sudo gem install cocoapods
