Copyright 2006 Nanorex, Inc.  See LICENSE file for details. 

To merge new parameters into the parameter files (stretch.parms and
bending.parms), with new parameters overriding older ones:

sort --stable --key=1,1 newfiles oldfiles | uniq --check-fields=1

--stable means that lines whose sort fields are identical will be left
in their original order, instead of being sorted by the entire line.
This will cause newer parameters to preceed older ones.  uniq will
print the first line, selecting the newer parameter.

The --key and --check-fields options cause the commands to work on
only the first field on each line.

To look at the parameters that are being overridden:

diff oldparams newparams | sed '/^[^<>]/d' | sort --stable --key=2,2 |
   uniq --skip-fields=1 --check-fields=1 --all-repeated

The sed leaves only lines starting with < or >.  The stable sort
places the same parameters next to each other, and the uniq removes
lines that were mearly added or left unchanged.  Note that we have to
skip the first field in both sort and uniq, since it's just the < or
>.