sort -nu

[2004]

Although not a bug, sort's documentation might be wise to explicitly
mention that -u's behaviour is effected by options like -n.  The following
example was not what I expected, though I now understand why.  -u's
behaviour being effected by other options is powerful if understood, but
dangerous if not.  Thanks a million for all your efforts, GNU!

# sort -n -u < example_input |wc
     26      52     750
# sort -n < example_input | sort -u |wc
    219     438    6230

example_input
Description: Text document