stable sort in unix tools?

[Kurt Indermaur]

I'm stuck with a little sorting problem... not big enough to write my own
sorting routine, but annoying nevertheless.  I have a file with lines like:

1237    A2      text comments
1357    A3      more text
1644    A1      blah blah blah
1718    A1      still more

(sorted by the number in the first column) that I would like to get
sorted by the classification in the second column (A1, A2, A3...), but
keeping the numbers in order within each classification.  The above list,
for instance, would end up:

1644    A1      blah blah blah
1718    A1      still more
1237    A2      text comments
1357    A3      more text

I need a stable sort, in other words, and the standard (4.3 bsd) UNIX sort
doesn't seem to provide that.  Is there a way around this using UNIX tools?
Is there another way?  Any help (including programs, if necessary) would be
appreciated.

Please respond by e-mail... I don't often get the chance to read this group.

Thanks,

Kurt Indermaur
(indermau at dg.cs.umn.edu)