How To Create Patches Using diff

Use "diff -up" or "diff -uprN" to create patches with diff(1).

When creating your patch, make sure to create it in "unified diff" format, as supplied by the '-u' argument to diff(1).

Also, please use the '-p' argument which shows which C function each change is in - that makes the resultant diff a lot easier to read.

To create a patch for a single file, it is often sufficient to do:

    SRCTREE= trunk
    MYFILE=  package/base-files/Makefile
    cd $SRCTREE
    cp $MYFILE $MYFILE.orig
    vi $MYFILE    # make your change
    cd ..
    diff -up $SRCTREE/$MYFILE{.orig,} > /tmp/patch

To create a patch for multiple files, you should checkout a "vanilla", or unmodified OpenWrt source tree, and generate a diff against your own source tree. For example:

    MYSRC= /devel/openwrt/trunk
    svn co svn://svn.openwrt.org/openwrt/trunk/
    diff -uprN trunk $MYSRC > /tmp/patch

If you are going to include a diffstat after the "---" marker, please use diffstat options "-p 1 -w 70" so that filenames are listed from the top of the kernel source tree and don't use too much horizontal space (easily fit in 80 columns, maybe with some indentation).