ed Scripts
diff can produce output that is like an ed script, but
with hunks in forward (front to back) order. The format of the commands
is also changed slightly: command characters precede the lines they
modify, spaces separate line numbers in ranges, and no attempt is made
to disambiguate hunk lines consisting of a single period. Like
ed format, forward ed format cannot represent incomplete
lines.
Forward ed format is not very useful, because neither ed
nor patch can apply diffs in this format. It exists mainly for
compatibility with older versions of diff. Use the `-f' or
`--forward-ed' option to select it.