Utility to change a byte in a binary file?

[V.I.Victor]

It sure seems that this should be simple, but my searches have only turned up inter-active hex/disk editors.  I'm probably "asking" wrong.

I have a large binary file (>700 meg) and I know that there is a single wrong byte.  I also know it's exact location in the file.

Is there a command-line utility to write a byte at a specified offset into a file?