**
** Only the main repository database is backed up by this command.  The
** open checkout file (if any) is not saved.  Nor is the global configuration
** database.
**
** Options:
**
**    --overwrite              Ok to overwrite an existing file.
**    --overwrite              OK to overwrite an existing file.
**    -R NAME                  Filename of the repository to backup
*/
void backup_cmd(void){
  char *zDest;
  int bOverwrite = 0;
  db_find_and_open_repository(OPEN_ANY_SCHEMA, 0);
  bOverwrite = find_option("overwrite",0,0)!=0;