# 19.4 Binary patch

The '-r' flag of `radiff` will make it dump radare commands instead of human readable information. These commands if applied will make the first binary be the same as the second one. For example, have a look on this unit test:

    $ cat tests/chk/radiff-test.sh
    #!/bin/sh
    printf "Checking radiff -rd... "
    cp /bin/true .
    radiff -rd true /bin/false | radare -vnw true
    RET=`radiff -d true /bin/false`
    if [ -n "${RET}" ]; then
            echo "Failed"
    else
            echo "Success"
    fi
    rm -f true

Piping the output of radiff -r into radare opening in read-write mode the original file will modify it to make the contents be the same as the second one.