code: def construct_blastall_cmdline(
      fname1, fname2, outdir, blastall_exe=pyani_config.BLASTALL_DEFAULT
  ):
      
      fstem1 = os.path.splitext(os.path.split(fname1)[-1])[0]
      fstem2 = os.path.splitext(os.path.split(fname2)[-1])[0]
      fstem1 = fstem1.replace("-fragments", "")
      prefix = os.path.join(outdir, "%s_vs_%s" % (fstem1, fstem2))
      cmd = (
          "{0} -p blastn -o {1}.blast_tab -i {2} -d {3} "
          + "-X 150 -q -1 -F F -e 1e-15 "
          + "-b 1 -v 1 -m 8"
      )
      return cmd.format(blastall_exe, prefix, fname1, fname2)
docs: Returns a single blastall command.
  
      - blastall_exe - path to BLASTALL executable