NAME

     holdif  - replace corresponding data on ntap1 with  that  on
     ntap2.

SYNOPSIS

     holdif [-N1 ntap1] [-N2 ntap2] [-O otap] [-rs irs] [-re ire]
     [-ns  ns] [-ne ne] [-s ist] [-e iend] [-3d] [-hw3d hwd] [-V]
     [-?]

DESCRIPTION

     holdif replaces the corresponding data  (via  RecNum/TrcNum)
     on ntap1 with that found on ntap2.  Both input datasets must
     have the same number of samples (NumSmp) and the same sample
     interval  (SmpInt).   This  program is designed to allow the
     user to pull off part of the dataset, do some processing  on
     that  partial  dataset,  and  then substitute that part back
     into the original dataset.  WARNING: If you edit off part of
     the  dataset to make changes on, DO NOT RENUMBER the partial
     dataset.  If you do, when you run holdif, you will  not  get
     the  changes  put  into  the  proper  place  in the original
     dataset (-N1).

     holdif gets both its data and its  parameters  from  command
     line arguments.  These arguments specify the inputs, output,
     record, trace, and time delimiters, and verbose printout, if
     desired.  Input dataset 2 may be piped into the program, and
     the output dataset may be piped out.

     NOTE:  this program assumes that the records  on  ntap1  are
     numbered  in  ascending order, the traces within each record
     are numbered in ascending order, AND that the data on  ntap2
     is  in the same order.  The numbering must be ascending, but
     not necessarily  consecutive.   Otherwise,  who  knows  what
     you'll get output.

  Command line arguments
     -N1 ntap1
          Enter the input dataset name or file immediately  after
          typing  -N1.  This input dataset contains the data that
          will be written  to  the  output  dataset,  except  for
          corresponding  RecNum,TrcNum  traces  on  ntap2.   This
          input file should include the complete path name if the
          file   resides   in  a  different  directory.   Example
          -N1/b/vsp/dummy tells the  program  to  look  for  file
          'dummy' in directory 'vsp' stored on the 'b' disk.

     -N2 ntap2
          Enter the input dataset name or file immediately  after
          typing  -N2  unless the inp ut is from a pipe, in which
          case the -N2 entry must be omitted.   This  dataset  is
          required  and  there is no default.  This input dataset
          contains the data that will be written  to  the  output
          dataset,  replacing  corresponding RecNum,TrcNum traces
          on ntap1.  This input file should include the  complete
          path  name if the file resides in a different directory
          (see above).  WARNING: If you  edit  off  part  of  the
          dataset to make changes on, DO NOT RENUMBER the partial
          dataset.  If you do, when you run holdif, you will  not
          get the changes put into the proper place in the origi-
          nal dataset (-N1).

     -O otap
          Enter the output dataset name or file immediately after
          typing  -O.  This output file is not required when pip-
          ing the output to another process.  The output  dataset
          also requires the full path name (see above).

     -rs irs
          Enter start sequential process record number.   Sequen-
          tial  record  numbers below this value will not be out-
          put. Default value is the first record.

     -re ire
          Enter end sequential process record number.  Sequential
          record  numbers  above  this  value will not be output.
          Default value is last record.

     -ns ns
          Enter start sequential process trace  number.   Sequen-
          tial trace numbers below this value will not be output.
          Default value is the first trace of each record.

     -ne ne
          Enter end sequential process trace number.   Sequential
          trace  numbers  above  this  value  will not be output.
          Default value is last trace of each record.

     -s   Enter the start time to output, in ms.   Default  value
          is start of trace.

     -e   Enter the end time to output, in ms.  Default value  is
          end of trace.

     -3d  Enter the command line argument '-3d' to use  3  dimen-
          sional  indexing.   If flagged the next entry should be
          considered as a third  header  slot  will  need  to  be
          checked.  DstSgn will be used by default.

     -hw3d hwd
          Enter the trace header mnemonic to use in  addition  to
          RecNum,  TrcNum for the third index.  This is only used
          with the -3d option above.  The default is DstSgn.


     -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.

EXAMPLE

     holdif -N1ntap1 -N2ntap2 -Ootap

     where we are using the defaults to output the same number of
     records  and traces as are on ntap1.  We are also defaulting
     to output the same number of samples as are  on  both  input
     datasets.

BUGS

     Bound to be some.  Contact Marilyn Miller, ATTC, x3593.

AUTHOR

     Marilyn A. Miller, USP team, EPTG.

COPYRIGHT

     copyright 2001, Amoco Production Company
               All Rights Reserved
          an affiliate of BP America Inc.