Newly imported sort(1) works slightly differently. In fact, the old
sort(1) had a bug and the tests invoked sort(1) the wrong way.
if cmp -s y x1; then : ; else echo Error on sort test 2; fi
sort -r <x1 >x2
if cmp -s x2 z; then : ; else echo Error on sort test 3; fi
-sort +1 -n <x |head -1 >y
+sort -k 2n <x |head -1 >y
echo "bibelot 3" >z
if cmp -s y z; then : ; else echo Error on sort test 4; fi
END
prep x | sort | uniq -c >y1
-sort +1 <y1 >y
+sort <y1 >y
if cmp -s y answer; then : ; else echo Error in pipeline test 1; fi
cat $f $f $f | sort | uniq >x