$ mkdir somewhere

$ cat > foo.orig
< 1
<
< 3
<
< 5
$ sed -e 's/3/3a/' foo.orig > foo
$ diff -u foo.orig foo > foo.diff
$ mv foo.orig foo

$ mkdir ${QUILT_PATCHES:-patches}
$ patch-wrapper -s -p0 < foo.diff
$ quilt pop -q
> Removing patch %{P}foo.diff
> No patches applied
$ rm -rf ${QUILT_PATCHES:-patches} ${QUILT_PC:-%{QUILT_PC}}

$ mkdir ${QUILT_PATCHES:-patches}
$ patch-wrapper --backup -B xxx/ -s -p0 < foo.diff
$ find xxx -type f
> xxx/foo
$ quilt pop -q
> Removing patch %{P}foo.diff
> No patches applied
$ rm -rf ${QUILT_PATCHES:-patches} ${QUILT_PC:-%{QUILT_PC}}

$ mkdir ${QUILT_PATCHES:-patches}
$ patch-wrapper -s -p0 -i foo.diff
$ quilt pop -q
> Removing patch %{P}foo.diff
> No patches applied
$ rm -rf ${QUILT_PATCHES:-patches} ${QUILT_PC:-%{QUILT_PC}}

$ mkdir ${QUILT_PATCHES:-patches}
$ patch-wrapper -p0 < foo.diff
> patching file foo
$ quilt pop -q
> Removing patch %{P}foo.diff
> No patches applied
$ rm -rf ${QUILT_PATCHES:-patches} ${QUILT_PC:-%{QUILT_PC}}

$ mv foo.diff somewhere/
$ mkdir ${QUILT_PATCHES:-patches}
$ patch-wrapper -p0 < somewhere/foo.diff
> patching file foo
$ quilt pop -q
> Removing patch %{P}somewhere/foo.diff
> No patches applied
$ rm -rf ${QUILT_PATCHES:-patches} ${QUILT_PC:-%{QUILT_PC}}

$ mkdir ${QUILT_PATCHES:-patches}
$ patch-wrapper -p0 -i somewhere/foo.diff
> patching file foo
$ quilt pop -q
> Removing patch %{P}somewhere/foo.diff
> No patches applied
$ rm -rf ${QUILT_PATCHES:-patches} ${QUILT_PC:-%{QUILT_PC}}

$ sed -e 's/5/5b/' foo > foo.new
$ mv foo.new foo
$ mkdir ${QUILT_PATCHES:-patches}
$ patch-wrapper -p0 < somewhere/foo.diff
> patching file foo
> Hunk #1 succeeded at 1 with fuzz 1.
$ cat foo.orig
> 1
>
> 3
>
> 5b
$ quilt pop -q
> Removing patch %{P}somewhere/foo.diff
> No patches applied
$ rm -rf ${QUILT_PATCHES:-patches} ${QUILT_PC:-%{QUILT_PC}}