To configure Android SDK environment variable on MacOS, use below steps:
Step 1: Open Terminal
Step 2: Open .bash_profile file, using either of below command:
$ open .bash_profile
$ vim .bash_profile
if the file is not already created and you want to use open filename, first you need to create it using below command
$ touch .bash_profile
Step 3: Paste following lines in .bash_profile, you need to replace tarungoswami with your username
export ANDROID_HOME=/Users/tarungoswami/Library/Android/sdk
export PATH=$ANDROID_HOME/platfor:wqm-tools:$PATH
export PATH=$ANDROID_HOME/tools:$PATH
Step 4: Save file opened using vim editor by typing :wq
Step 5: Use source command
$ source .bash_profile
Step 6: Type in terminal command adb , command should be found.