Given the following file :
> cat list2
1
1
2
A
B
Now try sorting it. First with just "-u" (sort uniquely) :
> sort -u list2
1
2
A
B
Now add "-n" to sort numerically (if the field looks like a number) :
> sort -un list2
A
1
2
Where did the "B" go ??
I've seen this in sort under Solaris 8, the GNU version in Ubuntu 7.04 and the gnuwin32 version on Windows. Surely it's a bug ?