OT: Calling unix experts, Need "vi" assistance Options

[Rusty]

Sorry for the OT post.

I have a text file that I need to edit.

I need to edit every record on that file (record positions 34-37) to change whatever is in those positions (only) to a four digit number. What is currently in those positions varies dramatically.

My only text editor I have on the system is vi.

Anyone got a command I can use?

thanks,
Lawrence

[Rusty]

Here's a sample record:

000104659 W91XLM40940026 GSA00001000011BA042200418504208W91XLM40940026XXXBY

I need to replace the four characters after BA0... "4220".

It shouldn't matter, but that's a julian date.

Unfortunately, the only option I have is to use the existing system (with real VI, on a stripped down version of Solaris), unless I want to use get/dosput to bring them over to my Windows system. I dunno copying them back will screw up their formatting.

thanks for the input (no pun intended!)