pg_archivecleanup — clean up PostgreSQL WAL archive files
pg_archivecleanup [option...]  archivelocation   oldestkeptwalfile 
  pg_archivecleanup is designed to be used as an
  archive_cleanup_command to clean up WAL file archives when
  running as a standby server (see Section 26.2).
  pg_archivecleanup can also be used as a standalone program to
  clean WAL file archives.
 
   To configure a standby
   server to use pg_archivecleanup, put this into its
   postgresql.conf configuration file:
archive_cleanup_command = 'pg_archivecleanup archivelocation %r'
   where archivelocation is the directory from which WAL segment
   files should be removed.
  
   When used within archive_cleanup_command, all WAL files
   logically preceding the value of the %r argument will be removed
   from archivelocation. This minimizes the number of files
   that need to be retained, while preserving crash-restart capability.  Use of
   this parameter is appropriate if the archivelocation is a
   transient staging area for this particular standby server, but
   not when the archivelocation is intended as a
   long-term WAL archive area, or when multiple standby servers are recovering
   from the same archive location.
  
   When used as a standalone program all WAL files logically preceding the
   oldestkeptwalfile will be removed from archivelocation.
   In this mode, if you specify a .partial or .backup
   file name, then only the file prefix will be used as the
   oldestkeptwalfile. This treatment of .backup
   file name allows you to remove
   all WAL files archived prior to a specific base backup without error.
   For example, the following example will remove all files older than
   WAL file name 000000010000003700000010:
pg_archivecleanup -d archive 000000010000003700000010.00000020.backup pg_archivecleanup: keep WAL file "archive/000000010000003700000010" and later pg_archivecleanup: removing file "archive/00000001000000370000000F" pg_archivecleanup: removing file "archive/00000001000000370000000E"
   pg_archivecleanup assumes that
   archivelocation is a directory readable and writable by the
   server-owning user.
  
pg_archivecleanup accepts the following command-line arguments:
-b--clean-backup-historyRemove backup history files as well. See Section 25.3.2 for details about backup history files.
-d--debug
        Print lots of debug logging output on stderr.
       
-n--dry-run
        Print the names of the files that would have been removed on stdout (performs a dry run).
       
-V--versionPrint the pg_archivecleanup version and exit.
-x extension--strip-extension=extension
        Provide an extension
        that will be stripped from all file names before deciding if they
        should be deleted.  This is typically useful for cleaning up archives
        that have been compressed during storage, and therefore have had an
        extension added by the compression program.  For example: -x
        .gz.
       
-?--helpShow help about pg_archivecleanup command line arguments, and exit.
   The environment variable PG_COLOR specifies whether to use
   color in diagnostic messages. Possible values are
   always, auto and
   never.
  
pg_archivecleanup is designed to work with PostgreSQL 8.0 and later when used as a standalone utility, or with PostgreSQL 9.0 and later when used as an archive cleanup command.
pg_archivecleanup is written in C and has an easy-to-modify source code, with specifically designated sections to modify for your own needs
On Linux or Unix systems, you might use:
archive_cleanup_command = 'pg_archivecleanup -d /mnt/standby/archive %r 2>>cleanup.log'
   where the archive directory is physically located on the standby server,
   so that the archive_command is accessing it across NFS,
   but the files are local to the standby.
   This will:
  
     produce debugging output in cleanup.log
    
remove no-longer-needed files from the archive directory