Linux Sort command

Question

Hello,

I would like to know which sorting algorithm the linux SORT command uses?

Answer 1

mergesort

It¹ uses mergesort rather than quicksort or heapsort for two reasons:

• mergesort is a stable sort and typically the efficient quicksort implementations are not
• while it may do more swaps or moves it does fewer comparisons and so tends to work better with text input

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^{1. Linux distros are free to choose their own sort utility but I imagine virtually all use GNU sort so I have described that.}

Answer 2

An External R-Way merge sort according to Algorithm details of UNIX Sort Command. Found via this stackoverflow question.