18.1. The PostgreSQL User Account
  As with any server daemon that is accessible to the outside world,
   it is advisable to run
  
   PostgreSQL
  
  under a
   separate user account. This user account should only own the data
   that is managed by the server, and should not be shared with other
   daemons. (For example, using the user
  
   nobody
  
  is a bad
   idea.) In particular, it is advisable that this user account not own
   the
  
   PostgreSQL
  
  executable files, to ensure
   that a compromised server process could not modify those executables.
 
Pre-packaged versions of PostgreSQL will typically create a suitable user account automatically during package installation.
  To add a Unix user account to your system, look for a command
  
   useradd
  
  or
  
   adduser
  
  . The user
   name
  
   postgres
  
  is often used, and is assumed
   throughout this book, but you can use another name if you like.