A copy-patch records the copy operation of the file system.

The patch may be denoted as: **copy** *from to*

This is equivalent to: **addfile** *to*; **hunk** ''to 1 <content
of from>

Its pro over the equivalent form is that it documents the
connection of from and to.

It commutes with all patches but

-  hunk from ... this satisfies:
-  hunk from X ; copy from to = copy from to; hunk to X; hunk from
   X
-  copy from to ; hunk from X = hunk from X; copy from to; hunk to
   X\_inverse
-  addfile to
-  addfile to ; copy from to = error
-  copy from to ; addfile = error
-  hunk to
-  hunk to X ; copy from to = error
-  copy from to ; hunk to X = hunk from X ; copy from to; hunk from
   X\_inverse
-  remove from
-  remove from ; copy from to = error
-  copy from to ; remove from = rename from to
-  remove to
-  remove to; copy from to = hunk to <remove all;insert content of
   from>
-  copy from to; remove to = <nothing>