[YLUG] How do to substition in a file with sed or similar

[mjpb100 at york.ac.uk]

On Oct 27 2006, Charles Forsyth wrote:

> see the `overwrite' command in Kernighan and Pike:
> 
> 	overwrite myfile sed 's/fool/bar' myfile
> and it's useful for tr and commands with similar interfaces

alternatively you can use the -i flag for GNU sed (but only GNU).