Reinstate `spago script`

[f-f]

Still needs to be ported from the Haskell implementation, see here

[JordanMartinez]

This may require changes in node-execa first as I don't think it'll handle multi-line shebangs properly right now (or this might only be the case on Windows). See https://github.com/JordanMartinez/purescript-node-execa/blob/master/src/Node/Library/Execa/CrossSpawn.purs#L181-L188

[f-f]

This should now be unblocked?

[JordanMartinez]

Yes and no. For Linux/Mac, this is unblocked. For Windows, this is unblocked but may not work correctly in all cases. In node-execa (as noted above), we only read the first 150 bytes of a file. If there are multi-line shebangs that make up the entire command, we'll drop some of that on Windows.

[f-f]

Do we know why that 150? Is that just a number that is deemed "good enough" to read all the shebang lines?

[JordanMartinez]

Is that just a number that is deemed "good enough" to read all the shebang lines?

AFAICT, yes. That's what was in the original code. I can't recall whether there was a comment explaining why.

[f-f]

150 chars should be quite enough for the majority of cases, we can try shipping this and come back to bump it if we ever figure out it's not enough

[JordanMartinez]

It's your call.

[f-f]

Let's