When you run that it should create a fly.toml on your current working dir
$ fly launch --image flyio/redis:6.2.6 --no-deploy
Creating app in /Users/lubien/workspace/fly-tests
Using image flyio/redis:6.2.6
? App Name (leave blank to use an auto-generated name):
? Select organization: Lubien (personal)
? Select region: gru (São Paulo)
Created app holy-hill-259 in organization personal
Wrote config file fly.toml
Your app is ready. Deploy with `flyctl deploy`
$ fly-tests % ls
fly.toml