What do the permissions -rwSr-xr-x mean for a binary file when it is executed as a command?

Execution with the owner's effective rights via SetUID requires a lowercase `s` in the owner execute field, meaning both SetUID and execute are set; the uppercase `S` here negates that behavior.

Execution with the group's effective rights is controlled by the SetGID bit, which appears in the group execute position, not the owner execute position shown here.

Unix encodes SetUID in the owner execute slot as lowercase `s` when the execute bit is also set, and as uppercase `S` when the execute bit is missing. Because the owner has no execute permission here, the kernel cannot launch the process in an elevated context, and the SetUID flag has no effect - the binary simply cannot be run with elevated owner rights.

No standard Unix permission bit simultaneously grants both owner and group effective rights; SetUID and SetGID are independent bits affecting different privilege contexts.