Yeah thanks for your reply. I was thinking about using sed the other night and found out it was far easier to do what i was after than awk. However i have run into another problem.

How do i replace for example:

BIAS UD=34 UG=20

so if i wanna replace UG=20 with UG=30 i can use sed 's/UG=20/UG=30/'' ...easy.

But i am incrementing a UG from the command line so i need to change the UG occurrence already in the file with my new one ...eg:

INC=40

sed 's/UG=*/UG='$INC'/' i need to be able to change UG=* in the file where star is any value...is there anyway to take star as wildcard instead of literally? sorry for my poor english. Its hard to explain my problem.