Current user documentation contains the following command
which is used to create user in postgresql:
createuser -U postgres -d -A -P dspace
Flag -A isn't mentioned in the official postgresql documentation:
The command works fine with the flag but it also works without it
but it seems that correct command line wouldn't contain -A.
Interestingly I've found similar problem here:
This might lead to the origin of this non-existent flag but
I was not able to find out where it comes from.