Just save ilp_creds.sh to your machine, and run source ./ilp_creds.sh in bash.
It will fetch you XRP testnet credentials from the faucet, and export them into your shell in
the variables ILP_CREDENTIALS and ILP_PLUGIN.
In this shell, you can now use ILP tools such as ilp-curl, which will use your new testnet credentials.
To save your testnet credentials into your .bashrc, run:
echo "export ILP_CREDENTIALS=$ILP_CREDENTIALS" >> ~/.bashrc
echo "export ILP_PLUGIN=$ILP_PLUGIN" >> ~/.bashrc