I'm trying to sort (and ideally remove duplicate lines) from a 1.4TB file.
Splitting and sorting the individual chunks is not an issue, but reassembling them is turning out to be a challenge. I expected from the man page that 'sort -m' (Under FreeBSD 11) would do a simple merge, creating an aggregate perfectly sorted output, optionally suppressing duplicates with the -u option.
But after leaving it to run for a while, I discovered that sort had (so far) generated several hundred gigs worth of temporary files, just as if it was sorting the input like normal.
I don't have enough disk space to be able to store the same data 3 times. Are there any utilities that can do a simple merge of already sorted files, without requiring temporary disk space?
=== Outcome ===
I ended up using a "standard" sort. It took around 50 hours of high CPU and disk load to process, including the generation of several hundred temporary files. This was despite the input already being perfectly sorted. I'm still interested in learning if there is a simple utility to neatly merge pre-sorted files.