$ mkdir patches $ echo a > a $ echo b > b $ diff -u a b > patches/patch $ echo patch -p0 > patches/series $ rm -f b $ quilt push -q > Applying patch patches/patch > Now at patch patches/patch $ quilt pop -q > Removing patch patches/patch > No patches applied $ patch -s -p0 < patches/patch $ quilt push -q > Applying patch patches/patch > 1 out of 1 hunk FAILED > Patch patches/patch can be reverse-applied $ echo patch -p0 -R > patches/series $ quilt push -q > Applying patch patches/patch > Now at patch patches/patch $ quilt pop -q > Removing patch patches/patch > No patches applied $ patch -s -p0 -R < patches/patch $ quilt push -q > Applying patch patches/patch > 1 out of 1 hunk FAILED > Patch patches/patch can be reverse-applied