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SU News 03/17/91

We are beginning to accumulate a set of really nifty Korn shells
for doing seismic processing.  Dave got us started, and lately
Ken has been constructing some examples with intriguing names
like Filtertest, Nmoscan, etc.

I'm editing (ie. generalizing, reorganizing) on a collection of
the "Best of Dave and Ken" and expect it to become a best seller.
I'll let you know when I get it ready.

Meanwhile, here is a nifty hack I've discovered (and use extensively
in these shells) for doing float calculations in shell scripts:
-----
#! /bin/sh
pi=3.14159
a=`bc << EOF
	$pi * 2
EOF`
echo $a
-----
#! /bin/ksh
pi=3.14159
a=$(bc <<-EOF
	$pi * 2
EOF)
print $a
-----

And now I'll announce two of the most trivial codes you can imagine:

New program: sunull---construct file of null (all zeroes) traces
Remark1: This is one I've actually written many times, but this is
	the first time I *meant* to get an all-zero section.  The immediate
	application is to use it in a shell loop to get some space between
	"panels" of actual data for clarifying screen displays.
Remark2: sunull might be considered as Chris's suzero carried to the limit
Remark3: Thx to Serge for the idea

New program: sushape---compute filter that shapes given wavelet
	into desired wavelet and apply it to the traces
Remark 1: suascii can be used to capture a segment of a trace (wavelet).
Remark 2: If someone writes a wavelet estimation program, we'll really
	have something, otherwise this is mainly for use in putting
	desired wavelets on synthetic traces.