$ rm -rf d
$ mkdir -p d/patches d/subdir
$ cd d

$ cat > editor
< #! /bin/sh
< echo Editing $1
< echo foo > $1
$ chmod +x editor
$ export EDITOR=%PWD/editor

$ quilt new patch
> Patch patches/patch is now on top
$ cd subdir
$ quilt edit foo
> File subdir/foo added to patch ../patches/patch
> Editing foo

$ cd ../..
$ rm -rf d