Shell Programming and Scripting

Hi
I have a file in the foll. format
*RECORD*
*FIELD NO*
.......
.......
*FIELD TX*
Data
*FIELD AV*
Data
*FIELD RF*


*RECORD*
*FIELD NO*
.......
.......
*FIELD TX*
Data
*FIELD RF*


i.e. Some records have *FIELD AV* between *FIELD TX* and *FIELD RF*

I want to insert *FIELD AV* between *FIELD TX* and *FIELD RF* IF it does not exist already.

Any input on such a script would be helpful

Please provide sample input and expected output. The sample input should cover all cases

There may be a way in 'awk' to do this but I tend to use 'sed' on the command line and 'perl' for more complex tasks.

Code:

#!/usr/bin/perl -w

open(IN, "< test");
open(OUT, ">output");

$AV=0;

while ($line = <IN>) {
  if ($line =~ m/FIELD AV/) {
    $AV=1;
    print OUT "$line";
  }
  elsif ($line =~ m/FIELD RF/) {
    if ($AV == 0) {
      print OUT "*FIELD AV*\n";
      $AV=0;
    }
    else {
      $AV=0;
    }
    print OUT "$line";
  }
  else {
    print OUT "$line";
  }
}

close(IN);
close(OUT);

Here's the sample input data. There are 2 records delimited by *RECORD*.
I want to extract data in the *FIELD* <fieldName>

-----------------------------------------------------------------------------------
*RECORD*
*FIELD* NO
100050
*FIELD* TI
100050 AARSKOG SYNDROME
*FIELD* TX
Grier et al. (1983) reported father and 2 sons with typical Aarskog
syndrome, including short stature, hypertelorism, and shawl scrotum.
They tabulated the findings in 82 previous cases.

*FIELD RF*
1. Grier, R. E.; Farrington, F. H.; Kendig, R.; Mamunes, P.: Autosomal
dominant inheritance of the Aarskog syndrome. Am. J. Med. Genet. 15:
39-46, 1983.


*RECORD*
*FIELD* NO
100650
*FIELD* TI
+100650 ALDEHYDE DEHYDROGENASE 2 FAMILY; ALDH2
;;ALDEHYDE DEHYDROGENASE 2;;

*FIELD* TX

DESCRIPTION

Acetaldehyde dehydrogenase (EC 1.2.1.3) is the next enzyme after alcohol
dehydrogenase (see 103700) in the major pathway of alcohol metabolism.
There are 2 major ALDH isozymes in the liver: cytosolic ALDH1 (ALDH1A1;
100640) and mitochondrial ALDH2.

CLONING

*FIELD* AV
.0001
ALCOHOL SENSITIVITY, ACUTE
HANGOVER, SUSCEPTIBILITY TO, INCLUDED;;

The designation for the ALDH2*2 polymorphism has been changed from
GLU487LYS to GLU504LYS. The numbering change includes the N-terminal
mitochondrial leader peptide of 17 amino acids (Li et al., 2006).

*FIELD* RF
1. Agarwal, D. P.; Harada, S.; Goedde, H. W.: Racial differences
in biological sensitivity to ethanol: the role of alcohol dehydrogenase
and aldehyde dehydrogenase isozymes. Alcoholism 5: 12-16, 1981.

3. Braun, T.; Grzeschik, K. H.; Bober, E.; Singh, S.; Agarwal, D.
P.; Goedde, H. W.: The structural gene for the mitochondrial aldehyde
dehydrogenase maps to human chromosome 12. Hum. Genet. 73: 365-367,1986.

-------------------------------------------------------------------------
DESIRED OUTPUT
-------------------------------------------------------------------------

*RECORD*
*FIELD* NO
100050
*FIELD* TI
100050 AARSKOG SYNDROME
*FIELD* TX
Grier et al. (1983) reported father and 2 sons with typical Aarskog
syndrome, including short stature, hypertelorism, and shawl scrotum.
They tabulated the findings in 82 previous cases.

*FIELD* AV <---- This is the new entry
*FIELD* RF
1. Grier, R. E.; Farrington, F. H.; Kendig, R.; Mamunes, P.: Autosomal
dominant inheritance of the Aarskog syndrome. Am. J. Med. Genet. 15:
39-46, 1983.


*RECORD*
*FIELD* NO
100650
*FIELD* TI
+100650 ALDEHYDE DEHYDROGENASE 2 FAMILY; ALDH2
;;ALDEHYDE DEHYDROGENASE 2;;

*FIELD* TX

DESCRIPTION

Acetaldehyde dehydrogenase (EC 1.2.1.3) is the next enzyme after alcohol
dehydrogenase (see 103700) in the major pathway of alcohol metabolism.
There are 2 major ALDH isozymes in the liver: cytosolic ALDH1 (ALDH1A1;
100640) and mitochondrial ALDH2.

CLONING

*FIELD* AV
.0001
ALCOHOL SENSITIVITY, ACUTE
HANGOVER, SUSCEPTIBILITY TO, INCLUDED;;

The designation for the ALDH2*2 polymorphism has been changed from
GLU487LYS to GLU504LYS. The numbering change includes the N-terminal
mitochondrial leader peptide of 17 amino acids (Li et al., 2006).

*FIELD* RF
1. Agarwal, D. P.; Harada, S.; Goedde, H. W.: Racial differences
in biological sensitivity to ethanol: the role of alcohol dehydrogenase
and aldehyde dehydrogenase isozymes. Alcoholism 5: 12-16, 1981.

3. Braun, T.; Grzeschik, K. H.; Bober, E.; Singh, S.; Agarwal, D.
P.; Goedde, H. W.: The structural gene for the mitochondrial aldehyde
dehydrogenase maps to human chromosome 12. Hum. Genet. 73: 365-367,1986.

---------------------------------------------------------------------------------

Goal: Introduce the term "*FIELD* AV" between *FIELD* TX and *FIELD* RF if it does not already exist.

Background:
The data is a free form text file in which the below order of fields must be maintained for every record.
*FIELD* NO
*FIELD* TI
*FIELD* TX
*FIELD* AV
*FIELD* RF

Currently the first 3 fields are being loaded correctly using bulk data loading utilities (SQL*Loader, etc.) but since the 4th field is missing in some records, it introduces a one-off error.

Any input on some preprocessing on the file using sed/awk to continue using SQL*Loader would be helpful

I would appreciate if any one could give a handy one-liner in sed/awk to insert a line between two lines if and only if a condition is NOT fulfilled

sample input record:
*field* 1
*field* 2
*field* 3

*field* 1
*field* 3


sample output record:
*field* 1
*field* 2
*field* 3

*field* 1
*field* 2
*field* 3


insert word between two lines if word does not occur
else
leave as is.

I know to do this in perl, but I am just looking for an awk/sed command that would accomplish the same.