添加全局環境變量

1. sudo cp /etc/bash.bashrc /etc/bash.bashrc_backup
2. sudo vim /etc/bash.bashrc

export ANDROID_HOME=/usr/local/android/sdk
export PATH=/usr/local/apktool:$PATH
export PATH=/usr/local/android/sdk/tools:$PATH

3. sudo -s
4. source /etc/bash.bashrc