gistfile1.sh

#!/bin/bash
if cat ~/.heroku/credentials | grep 654321 > /dev/null
then
 echo "me@gmail.com" > ~/.heroku/credentials
 echo "123456" >> ~/.heroku/credentials
else
 echo "myself@gmail.com" > ~/.heroku/credentials
 echo "654321" >> ~/.heroku/credentials
fi
cat ~/.heroku/credentials