Everything that I've read says that the 'su' command will change my Linux user ID but not my identity. Here's what I see: # id -Z root:staff_r:staff_t # su fred Your default context is fred:sysadm_r:sysadm_t. Do you want to choose a different one? [n]n $ id -Z fred:sysadm_r:sysadm_t My identity changed from 'root' to 'fred'. Bug? That seems a pretty fundamental flaw considering that every document that I've read uses 'su' to explain the difference between a user ID and an identity. By the way, I see the same result whether I use 'su' or 'su -'. I see the same result (a change in identity) whether I su from root to fred or from fred to root. So which one is right? The documentation or the code?