Downloading the phar with the recommended script can have odd results.

[KorvinSzanto]

Github is likely blocking certain user agents and so I end up getting Not found as the content of my phar instead of the actual phar:

main@cli:/app$ cat /usr/local/bin/concrete 
Not Found

It'd be nice to either fail the curl if we get this result and also to figure out what's causing it.

[mlocati]

I never experienced this error.

We may invoke curl with the -f flag so that it fails in case of errors.