Create patch file

Basic example to use "patch" command.

diff -Naur <absolute path of old file > <absolute path of new file>

# create a reverse patch file (just swap new and old file)
diff -Naur <absolute path of  new file> <absolute path of old file>

patch -r- -p0 -d / -N -i <absolute path of patch file>

# create a backup
patch -b -r- -p0 -d / -N -i <absolute path of patch file>

patch -R <absolute path of patched file> <absolute path of patch file>

Or, use "reverse patch file" to patch.

for i in *.orig; do
    base=`basename ${i} .orig`
    mv $i $base
done