Composer

curl -sS https://getcomposer.org/installer | php
mv composer.phar /usr/local/bin/composer

If your PATH is in .bashrc file :

echo 'export PATH="$PATH:$HOME/.config/composer/vendor/bin"' >> ~/.bashrc

# Restart your environment
source ~/.bashrc #Bash

If your PATH is in .zshrc file :

echo 'export PATH="$PATH:$HOME/.config/composer/vendor/bin"' >> ~/.zshrc

# Restart your environment
source ~/.zshrc #ZSH

PHPCS

  composer global require "squizlabs/php_codesniffer=*"

 composer global require friendsofphp/php-cs-fixer