Put this script in /usr/local/bin or anywhere you want.
Make sure to make the script executable.
This script download fastapt in /usr/local/bin and make it executable:
sudo curl -L "https://raw.githubusercontent.com/aqua47/Fastapt/refs/heads/main/fastapt" -o /usr/local/bin/fastapt && sudo chmod +x /usr/local/bin/fastapt