add default values to arguments of walk etc.
% new file
applying patch from stdin
patching file new
% chmod +x
applying patch from stdin
% copy
applying patch from stdin
a
a
% rename
applying patch from stdin
copyx
new
rename
% delete
applying patch from stdin
patching file copyx
new
rename
% regular diff
applying patch from stdin
patching file rename
% copy and modify
applying patch from stdin
patching file copy2
a
a
b
a
a
% rename and modify
applying patch from stdin
patching file rename2
copy2: No such file or directory
a
a
b
c
a