Adding new fields to an existing layout

Shell Programming and Scripting
1

Hi Everybody,
I have an layout file like below

f1 1 char 10,
f2 11 char 2,
f3 13 char 1,
lineend 14 char 1

Their I need to add a new field which would be like

f5 char 3,
f6 char 2

The o/p should be

f1 1 char 10,
f2 11 char 2,
f3 13 char 1,
f5 14 char 3,
f6 17 char 2
lineend 14 char 1 /* Note this should be the last field. */

Now my requirement is , I need to automate this process.
i.e the new field addtion f5 and f6 should be automated and the field name data type and the length will be given in a text file. We need to read that file and modify the layout. Can anyone help me how to approach this?

Note : For the new fields to be added, the spaces in between fields should be similar to the old fields.

2

Hi Manii,

a.txt is your existing file...

b.txt is file whith new data

cnt=`wc -l a.txt | awk '{print $1}'`
num=`expr $cnt - 1 | bc`
head -$num a.txt >> new.txt
cat b.txt >> new.txt
tail -1 a.txt >> new.txt
3

Here is code :

#! /bin/ksh

aa=" "
cnt=`wc -l a.txt | awk '{print $1}'`
num=`expr $cnt - 1 | bc`
head -$num a.txt >> new.txt
let i=1

let sec=`tail -1 new.txt | awk '{print $2}'`
las=`tail -1 new.txt | awk '{print $4}'`
let llas=`echo $las | awk -F, '{print $1}'`


bcnt=`wc -l b.txt | awk '{print $1}'`

while [ $i -le $bcnt ]
do
	col1=`head -$i b.txt| tail -1 | awk '{print $1}'`
	col2=`expr $sec + $llas | bc`
	col3=`head -$i b.txt | tail -1 | awk '{print $2}'`
	col4=`head -$i b.txt | tail -1 | awk '{print $3}'`
	echo "${col1}${aa}${col2}${aa}${col3}${aa}${col4}" >> new.txt
	let i=`expr $i + 1 | bc`
	let sec=$col2
	let llas=`echo $col4 | awk -F, '{print $1}'`
	
done
tail -1 a.txt >> new.txt