pg_verify_checksums — verify data checksums in a PostgreSQL database cluster
pg_verify_checksums [option...] [[ -D  |   --pgdata ] datadir]
   pg_verify_checksums verifies data checksums in a
   PostgreSQL cluster.  The server must be shut
   down cleanly before running pg_verify_checksums.
   The exit status is zero if there are no checksum errors, otherwise nonzero.
  
The following command-line options are available:
-D directory--pgdata=directorySpecifies the directory where the database cluster is stored.
-v--verboseEnable verbose output. Lists all checked files.
-r relfilenodeOnly validate checksums in the relation with specified relfilenode.
-V--versionPrint the pg_verify_checksums version and exit.
-?--helpShow help about pg_verify_checksums command line arguments, and exit.
PGDATA
      Specifies the directory where the database cluster is
      stored; can be overridden using the -D option.