pg_controldata — display control information of a PostgreSQL database cluster
pg_controldata [option] [[ --pgdata | -D ] datadir]
        pg_controldata prints information initialized during
        initdb, such as the catalog version.
        It also shows information about write-ahead logging and checkpoint
        processing. This information is cluster-wide, and not specific to any one
        database.
      
        This utility can only be run by the user who initialized the cluster because
        it requires read access to the data directory.
        You can specify the data directory on the command line, or use
        the environment variable PGDATA. This utility supports the options
        -V and --version, which print the
        pg_controldata version and exit. It also
        supports options -? and --help, which output the
        supported arguments.
      
PGDATADefault data directory location
PG_COLOR
              Specifies whether to use color in diagnostic messages. Possible values
              are always, auto and
              never.