That shell script above - you see where it displays "error" - if you make the script in a file with the execute bit set, you can run it. Use the portion that shows an error, i.e. "Skipping line" - and say, for example, "exit 1". Then at the end, assuming it didn't hit there, say "exit 0". Remove the printing where it's OK on A/B. Then your script exit value is zero/non-zero and you can use it as a test. Have it's input be from standard input, and it can "filter" for you. I realize this might be lots of theory and not enough specifics. If so, I could make it so and give you exact examples. Other folks here could too, I imagine. If you need it and no one has by the time I get back here, I'll do it.

Thanks for all the above help, but let me clarify the need of what is required to see if anyone can assist further.
Currently as stated i have teh following file called TEST1.CSV

ID ,, VALUE
A001 ,, 100
B002 ,, 200
A004 ,, 300
B006 ,, 100
A997 ,, 200
B776 ,, 400



This file needs to be processed but only if all the ID's are correct (that means only if the IDs begin with an A - B charcter.
If the ID begins with any character other A or B the process needs to exit out the script with error message.

What i would like is the following:

IF [begining of row is not A or B] THEN
print error message
exit 1
END IF

No else required as if the only A and B the IF statement will end succesfully leading the process scripting afterwards.
So any thoughts, not really as complex as previously thought???

OK i have found this to be teh best solution thus far, anyone with any better thoughts

if [ `cat TEST1.CSV | egrep -v '^A|^B' | wc -l` -gt 0 ]
then
echo "error message"
exit 1
fi

SAMZ, until now you didn't tell us what you really want to achieve. The logic you used is ok, but - depending on what you want to do, the part inside "carry on doing what you want" - there may or may not be better solutions. We are able to help you only if we know exactly what you want to achieve.

Maybe your way (that is: to do it in shell script language) is good, because the shell is best suited to what you want to achieve. The other solutions (awk, sed, ...) may or may not be better suited than your solution because the respective tools may or may not be better suited to what you want to do - to finally assess this question we would need to know what you want to do.

I hope this helps.

bakunin