Shell Programming and Scripting

Hi,

I have data file which has header, data and trailer.

The problem is that always the trailer is padded with the last line data.
i want to split the trailer and bring it to next line i.e end of line.

But i dont have any specific string to identify the trailer. Only way is that all data are 1234 characters. so i want to bring the last line characters from 1235 to next line.

Can anyone help on this

I don't fully understand what you are wanting to do here, but tail -c x should be able to get you the last x many characters.

If the last line of the file has more than 1234 characters, i want to cut the character position from 1235 to end of the line and put it as next line.

Example File:

HDR1234343545
abcdefghijklmnopqrst
TRLdefghijklmnopqrst
TRLdefghijklmnopqrst
abcdefghijklmnopqrst
abcdefghijklmnopqrst
abcdefghijklmnopqrstTRL0007

I want to cut the last line characters from 21 and make it as new line.

The output should be like this


HDR1234343545
abcdefghijklmnopqrst
TRLdefghijklmnopqrst
TRLdefghijklmnopqrst
abcdefghijklmnopqrst
abcdefghijklmnopqrst
abcdefghijklmnopqrst
TRL0007

Ah, now I understand... You want to insert a newline 1234 from the end of the file?

_way_ ugly but it should do the job.

Code:

#!/bin/sh
offset=$1
filename=$2
filesize=`wc -c $filename | awk '{ print $1 }'`
remainder=`expr $filesize - $offset`
echo $filesize $remainder $offset
dd bs=1 if=$filename count=$remainder 2> /dev/null
echo ""
tail -${offset}c $filename

scriptname.sh 1234 filename.txt