import os

   # The prefix to use for all output files  
   prefix=’ngc5921.usecase’  
 
   # Clean up old files  
   os.system(’rm -rf ’+prefix+’*’)

  CASA <2>: os.<tab>  
os.EX_CANTCREAT            os._Environ                os.fdatasync               os.remove  
os.EX_CONFIG               os.__all__                 os.fdopen                  os.removedirs  
os.EX_DATAERR              os.__builtins__            os.fork                    os.rename  
os.EX_IOERR                os.__class__               os.forkpty                 os.renames  
os.EX_NOHOST               os.__delattr__             os.fpathconf               os.rmdir  
os.EX_NOINPUT              os.__dict__                os.fstat                   os.sep  
os.EX_NOPERM               os.__doc__                 os.fstatvfs                os.setegid  
os.EX_NOUSER               os.__file__                os.fsync                   os.seteuid  
os.EX_OK                   os.__getattribute__        os.ftruncate               os.setgid  
os.EX_OSERR                os.__hash__                os.getcwd                  os.setgroups  
os.EX_OSFILE               os.__init__                os.getcwdu                 os.setpgid  
os.EX_PROTOCOL             os.__name__                os.getegid                 os.setpgrp  
os.EX_SOFTWARE             os.__new__                 os.getenv                  os.setregid  
os.EX_TEMPFAIL             os.__reduce__              os.geteuid                 os.setreuid  
os.EX_UNAVAILABLE          os.__reduce_ex__           os.getgid                  os.setsid  
os.EX_USAGE                os.__repr__                os.getgroups               os.setuid  
os.F_OK                    os.__setattr__             os.getloadavg              os.spawnl  
os.NGROUPS_MAX             os.__str__                 os.getlogin                os.spawnle  
os.O_APPEND                os._copy_reg               os.getpgid                 os.spawnlp  
os.O_CREAT                 os._execvpe                os.getpgrp                 os.spawnlpe  
os.O_DIRECT                os._exists                 os.getpid                  os.spawnv  
os.O_DIRECTORY             os._exit                   os.getppid                 os.spawnve  
os.O_DSYNC                 os._get_exports_list       os.getsid                  os.spawnvp  
os.O_EXCL                  os._make_stat_result       os.getuid                  os.spawnvpe  
os.O_LARGEFILE             os._make_statvfs_result    os.isatty                  os.stat  
os.O_NDELAY                os._pickle_stat_result     os.kill                    os.stat_float_times  
os.O_NOCTTY                os._pickle_statvfs_result  os.killpg                  os.stat_result  
os.O_NOFOLLOW              os._spawnvef               os.lchown                  os.statvfs  
os.O_NONBLOCK              os.abort                   os.linesep                 os.statvfs_result  
os.O_RDONLY                os.access                  os.link                    os.strerror  
os.O_RDWR                  os.altsep                  os.listdir                 os.symlink  
os.O_RSYNC                 os.chdir                   os.lseek                   os.sys  
os.O_SYNC                  os.chmod                   os.lstat                   os.sysconf  
os.O_TRUNC                 os.chown                   os.major                   os.sysconf_names  
os.O_WRONLY                os.chroot                  os.makedev                 os.system  
os.P_NOWAIT                os.close                   os.makedirs                os.tcgetpgrp  
os.P_NOWAITO               os.confstr                 os.minor                   os.tcsetpgrp  
os.P_WAIT                  os.confstr_names           os.mkdir                   os.tempnam  
os.R_OK                    os.ctermid                 os.mkfifo                  os.times  
os.SEEK_CUR                os.curdir                  os.mknod                   os.tmpfile  
os.SEEK_END                os.defpath                 os.name                    os.tmpnam  
os.SEEK_SET                os.devnull                 os.nice                    os.ttyname  
os.TMP_MAX                 os.dup                     os.open                    os.umask  
os.UserDict                os.dup2                    os.openpty                 os.uname  
os.WCONTINUED              os.environ                 os.pardir                  os.unlink  
os.WCOREDUMP               os.errno                   os.path                    os.unsetenv  
os.WEXITSTATUS             os.error                   os.pathconf                os.urandom  
os.WIFCONTINUED            os.execl                   os.pathconf_names          os.utime  
os.WIFEXITED               os.execle                  os.pathsep                 os.wait  
os.WIFSIGNALED             os.execlp                  os.pipe                    os.wait3  
os.WIFSTOPPED              os.execlpe                 os.popen                   os.wait4  
os.WNOHANG                 os.execv                   os.popen2                  os.waitpid  
os.WSTOPSIG                os.execve                  os.popen3                  os.walk  
os.WTERMSIG                os.execvp                  os.popen4                  os.write  
os.WUNTRACED               os.execvpe                 os.putenv  
os.W_OK                    os.extsep                  os.read  
os.X_OK                    os.fchdir                  os.readlink