Hi,

Bug #6366 was reported over a year ago to address a deficiency in "join":
it is unable to join on fields that are sorted numerically (rather than
lexicographically). The bug report has a patch attached -- I applied it to
the current Git head, cleaned up a few things, and added a couple tests.

In response to previous discussions on the issue, my two cents:
* "sort" includes several other sorting criteria, but they're not likely to
be useful in this context.
* This patch doesn't implement the functionality of sort's "-g" option, so
"-n" is appropriate.
* If two values have different string representations but compare as equal
due to lack of precision...well, the person doing the join should be aware
of the limits of floating point representations and use the "sort, join,
sort -n" strategy. I doubt this would come up much in practice though.

The lack of this option seems like an unusually conspicuous wart and I'd
love to see it addressed. Please let me know if I can be of any more help
to that effect.

Best,
Drew Frank