Inconsistency in exit codes returned by the scriggo command

[zapateo]

Currently, the scriggo command doesn't appear to follow any convention regarding exit codes when exiting the process.

In general, it seems to use:

• 0 for success (and that's fine)
• 1 or 2 interchangeably in other cases

If there's a pattern we already use, I haven't been able to determine it.

In general, we could follow the behavior of the go command, which seems to follow (from what I've seen) the gnu.org specification for Bash, which states:

All builtins return an exit status of 2 to indicate incorrect usage, generally invalid options or missing arguments.

So actually we could also standardize everything and follow a criterion like that.