Background:
Updated system 10.12.6, Xcode 9, IOS 11.0.1
Error: pod install abort
To solve reverse push: you need to upgrade Ruby Version to 2.2.2; you need to upgrade Homebrew Version (uninstall and reinstall); you need to upgrade common line tools;

Step 1: install HomeBrew / uninstall the update

#Why update HomeBrew?
//Report errors1: 
Error: /usr/local is not writable. You should change the
ownership and permissions of /usr/local back to your
Running Homebrew as root is extremely dangerous and no longer supported.
As Homebrew does not drop privileges on installation you would be giving all
build scripts full access to your system.

//Report errors2: 
Error running 'Requirements_oxs_brew_update_system ruby -2.3.3',
showing last 15 lines of /User/Lihongyuan/.rvm/log/848784602_ruby-2.3.3/update system.log
Requirements installation failed with status: 1.

//Report errors3: 
Error installing pods:active support requires Ruby version >= 2.2.2

sudo chown -R $(whoami) /usr/local
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/uninstall)"
cd /usr/local
git remote set-url origin git://mirrors.tuna.tsinghua.edu.cn/homebrew.git
cd ~
mkdir tmp
cd tmp
git clone git://mirrors.tuna.tsinghua.edu.cn/homebrew.git
sudo rm -rf /usr/local/.git
sudo rm -rf /usr/local/Library
sudo cp -R homebrew/.git /usr/local/
sudo cp -R homebrew/Library /usr/local/
rm -rf /usr/local/.git
rm -rf /usr/local/Cellar
ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"
Press RETURN to continue or any other key to abort,Please return in time,And enter the password to start the installation

Step 2: update commit line tools

#Error in installing Ruby Version:
Error running '__rvm_make -j 1',
showing last 15 lines of /Users/GDarkness/.rvm/log/1474100434_ruby-2.2.4/make.log

xcode-select --install
//Error reporting: Xcode is not currently available from the Software Update server

https://developer.apple.com/download/more/
Select the corresponding system and xcode version of tools to download and install

Step 3: update Ruby
RVM can be used to upgrade Ruby environment, that is, Ruby Version manager, Ruby Version manager.
RVM includes Ruby Version Management and Gem library management (gemset). RVM allows you to have multiple versions of ruby,
And you can freely switch between multiple versions.

curl -L get.rvm.io | bash -s stable
rvm -v
rvm list known
echo "ruby_url=https://cache.ruby-china.org/pub/ruby" > ~/.rvm/user/db
rvm install 2.2.2 --disable-binary

➜  ~ gem source
*** CURRENT SOURCES ***

http://rubygems-china.oss.aliyuncs.com
➜  ~ rvm current
ruby-2.2.2
➜  ~ rvm list

rvm rubies

   ruby-2.2.0 [ x86_64 ]
=* ruby-2.2.2 [ x86_64 ]

# => - current
# =* - current && default
#  * - default

➜  ~ rvm --default use 2.2.2
Using /Users/yun/.rvm/gems/ruby-2.2.2

#Why upgrade Ruby?
[1] 91225 abort pod install
pod install Unexpected exit in process, unable to generate new xcworkspace

#Why switch: pod can't be installed?
/Library/Ruby/Site/2.0.0/rubygems.rb:250:in
 `find_spec_for_exe': can't find gem cocoapods (>= 0.a) (Gem::GemNotFoundException)
    from /Library/Ruby/Site/2.0.0/rubygems.rb:278:in `activate_bin_path'
    from /usr/local/bin/pod:22:in `<main>'

Step 4: install pods

gem update —system
 Find the path to the pod 
which pod
 Delete files in directory 
sudo rm -rf /usr/local/bin/pod
 Get gem:
gem list
 Delete all pod s: 
gem uninstall cocoapods -v 0.39.0

gem sources -l
$gem sources --remove https://rubygems.org/
gem sources -a http://rubygems-china.oss.aliyuncs.com
#Uninstall cocoapods
sudo gem uninstall cocoapods
#Install the specified version
sudo gem install cocoapods --version 1.0.0

Step 5: pod install

#Wrong information
diff: /../Podfile.lock: No such file or directory  
diff: Manifest.lock: No such file or directory   
error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.`  

#Error occurred
pod install abort