NAME
editt - edit off selected portions of a data set
SYNOPSIS
editt [ -Nntap ] [ -Ootap ] [ -Frfile ] [ -hwhdrwrd ] [
-sist ] [ -eiend ] [ -S0sdel ] [ -nsnstr ] [ -nenetr ] [
-T0tdel ] [ -rsnrst ] [ -renred ] [ -R0rdel ] [ -tirst ] [
-tiirsti ] [ -uinst ] [ -uiinsti ] [ -lnew ] [ -U ] [ -P ] [
-match ] [ -V ] [ -EOF ] [ -? ]
DESCRIPTION
editt selects portions of an input data set and writes this
to an output data set. If the input data reside on disk
then the data may be accessed in either forwards or back-
wards order (e.g. start trace > end trace with negative
trace spacing). An attemp to access trace order backwards
while piping in will result in an error.
Record selection can also be made using a file of record
numbers either based on sequential record numbers or based
on matching values with numbers in the trace headers (nonse-
quential). Record selection using the command line input,
e.g. -rs[] is always assumed to represent sequential
numbers.
editt gets parameters from command line arguments or, in the
case of selecting records, from a flat file. These argu-
ments specify the input, output, the start and end times,
the start and end traces, the start and end records, and
verbose printout, if desired. In addition, options are pro-
vided to force change in the output number of traces per
record and to renumber the record and trace numbers.
When running editt inside IKP you have the options of either
attaching the input (unit 0) editt box to either a disk file
or socket (from another process), or giving the name of the
input disk file. Attaching a pipe permits editt to run
within a set of connected processes but allows only forward
editting: you cannot access data in reverse order and to get
to the selected records editt will read through all the data
in front of them, i.e. no skipping in a pipe. Grounding
unit 0 and giving a named disk file as input allows the user
to access the data in any order whatsoever but this requires
editt to be at the head of any set of connected process.
Another editt application is inside IKP is as a data server
at the head of a flow or as a data collector at the very
bottom of a flow. Sometimes if a flow is i/o bound (i.e.
processes are mostly waiting on data to arrive) putting an
editt at the top of a flow with the input on disk allows
large buffering to be used. This permits higher data read
rates from disk thus increasing the flow rate of data in the
rest of the piped flow. Similar reasoning applies to data
going out onto disk. The restriction here is that editt not
be used to limit traces, skip traces, or skip records.
Record limits (start/end) however may be used.
Command line arguments
-N ntap
Enter the input data set name or file immediately after
typing -N. This input file should include the complete
path name if the file resides in a different directory.
Example -N/b/vsp/dummy tells the program to look for
file 'dummy' in directory 'vsp' stored on the 'b' disk.
-O otap
Enter the output data set name or file immediately
after typing -O. This output file is not required when
piping the output to another process. The output data
set also requires the full path name (see above).
-F rfile
Enter the optional flat file containing record numbers
(one per line) to be selected. If the seismic data
reside on a disk file the records can be selected in
any order; if it comes in on a pipe the record numbers
must increase. If this file name is not given then
record select parameters are assumed to come from the
command line. These record numbers can be sequential or
actual (see match option).
-hw hdrwrd
Enter the trace header word referred to in rfile above
(-match option). Default = RecNum
-s ist
Enter the start time. The default is 0 units. Beware
that this routine does NOT look at TmMsFS from the line
header. It assumes that sample one is time zero.
-e iend
Enter the end time. The default is the end of the
trace.
-S0 sdel
Output every sdel samples starting at time ist. The
default is 1.
-ns nstr
Enter the start trace number. Trace numbers below this
value will not be output. The default is 1.
-ne netr
Enter the end trace number. Trace numbers above this
value will not be output. The default is the last
trace number on the input data set.
-T0 tdel
Output every tdel trace. The default is 1. To access
traces backwards ns should be larger then ne and tdel
should be negative. In the backwards case all three
entries must be specified even if ns or ne are the
first or last traces in a record.
-rs nrst
Enter start record number. Default value is the first
record.
-re nred
Enter end record number. Default value is last record.
-R0 rdel
Output every rdel record. The default is 1. To access
records backwards rs should be larger then re and rdel
should be negative. In the backwards case all three
entries must be specified even if rs or re are the
first or last records. Note: if a file of record
numbers is given the 3 above parameters are rendered
nonoperative.
-t irst
Enter starting record number of output (entry in line
header position RecNum). The default is 1
-ti irsti
Enter increment record number of output (entry in line
header position RecNum). The default is 1
-u inst
Enter starting trace number of output (entry in line
header position TrcNum). The default is 1
-ui insti
Enter increment trace number of output (entry in line
header position TrcNum). The default is 1
-l new
Enter new output traces per record. If this is not
exactly in synch with the input number of records and
traces and there is a partial last output record it
will be padded with dead (itr125 = 30000) traces.
-U Enter the command line argument '-U' to renumber the
record and trace numbers (trace header positions 106
and 107).
-P Enter the command line argument '-P' to output all
records except those sequential ones specified in file
rfile (see above). This is very useful if you have a
list of bad records you want to delete from a line.
All other record and trace limits are ignored if this
option is chosen.
-match
Enter the command line argument '-PP' to output records
having RecNum (formely hdr word 106) values that match
the values in the record number file above. If the pass
option is flagged all records from the input will be
output except those match RecNUm values with the values
in the file.
-EOF Enter the command line argument '-EOF' to force editt
to read to end of data set regardless of whether or not
it has selected all its data (and regardless of what it
thinks is in the line header). This is useful in an IKP
flow using the splitr "Y" function where the input data
is duplicated into multiple branches and you want to do
different editt's on each branch. If EOF is not set
then when editt finishes its last selection in the
first branch it will shut down the rest of the editt's
at that point.
-V Enter the command line argument '-V' to get additional
printout.
-? Enter the command line argument '-?' to get online
help. The program terminates after the help screen is
printed.
DISCUSSION
BUGS
The start time on the command line does not consider TmMsFS
from the line header. It assumes that sample one is time
zero. If this is not the case watch out.
SEE ALSO
wind(1)
AUTHOR
COPYRIGHT
copyright 2001, Amoco Production Company
All Rights Reserved
an affiliate of BP America Inc.
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