Hi developers,
It looks like I had misunderstanding of how `-k` works, by changing to -k
1,1 now it works.
However, this is confusing because 1) the behavior of `-n` and `-g` are not
consistent, 2) the `-n` in GNU sort is different from the sort on MacOS (which
has pos2 as pos1+1 instead of 0)… Best, Juncheng
