17.2. Getting the Source
  The
  
   PostgreSQL
  
  source code for released versions
   can be obtained from the download section of our website:
  
   https://www.postgresql.org/ftp/source/
  
  .
   Download the
  
   postgresql-
   
    
  or
  
     version
    
   
   .tar.gz
  
   postgresql-
   
    
  file you're interested in, then unpack it:
 
     version
    
   
   .tar.bz2
  
tar xf postgresql-version.tar.bz2
 
  This will create a directory
  
   postgresql-
   
    
  under
   the current directory with the
  
   PostgreSQL
  
  sources.
   Change into that directory for the rest of the installation procedure.
 
     version
    
   
  
Alternatively, you can use the Git version control system; see Section I.1 for more information.