Note that the code RavinderSingh13 suggested in post #2 in this thread will change the 35th character on every line; not just on lines where the original character in that position was "8".

For your second question you might want to try:

Code:

awk '
{	if(substr($0, 33, 3) == "008")
		print substr($0, 1, 32) "009" substr($0, 36)
	else	print
}' infile > outfile

It wasn't at all clear whether you wanted to make both changes in the same input file. If you do, the order in which you process the changes is very important. If you perform the two operations in the order you specified, the change of "008" to "009" will never happen since the "8" will already have been changed to a "7".

If what you want is to change "008" in character positions 33 through 35 (with the first position on a line being character position 1) and if there is a "8" in character position 35 where at least one of the characters in positions 33 and 34 is not "0", then you might want to try:

Code:

awk '
{	if(substr($0, 33, 3) == "008")
		print substr($0, 1, 32) "009" substr($0, 36)
	else	if(substr($0, 35, 1) == "8")
			print substr($0, 1, 34) "7" substr($0, 36)
		else	print
}' infile > outfile

And, as RavinderSingh13 already said, you need to tell us on every thread that you start what operating system and shell you're using. Both of the above scripts will work on most BSD, Linux, and UNIX operating systems, but will not work on Solaris/SunOS systems. On Solaris/SunOS systems, you'll need to change awk in both of the above scripts to either /usr/xpg4/bin/awk or nawk.