-S is quite useful. For bigger sorting tasks, I usually use -S50% to speed up the speed of sorting. (sort's default memory size must be about 1MB). It may also

-S is quite useful. For bigger sorting tasks, I usually use -S50% to speed up the speed of sorting. (sort's default memory size must be about 1MB). It may also help to use compression with the temporary files (something like "--compress-program lzop"), but I've never tried that.