N.1. When Color is Used
    
    
    
 
 
  To use colorized output, set the environment variable
  
   PG_COLOR
  
  
  
  as follows:
 
 
  
   - 
    
     If the value is
     
      always
     , then color is used.
 
- 
    
     If the value is
     
      auto
     and the standard error stream
      is associated with a terminal device, then color is used.
 
- 
    
     Otherwise, color is not used.