This is a technique to
* Reduce the size of install scripts
* Make them more forward compatible for the future
* Make them
== The Idea ==
The idea is simple: install by hand, make changes to make it work, then compare against the pristine sources, generating a patch that later does automatically what you did by hand
* Setup the app for installation as a webapp (say in html). Save a pristine copy as html.orign
* Make changes in html/ only
* Find out the diff of what you made:
diff -r -N -b -u html.orig html > app-patch.diff
* This then can go into the install script as follows:
patch -p0 -E << EOF
.... contents of app-patch.diff here ....
EOF
== Testing the patch ahead of time ==
It is strongly encouraged that you test the patch before attempting trial-and-error runs in the install script, which can be time consuming and error prone. This is basically simulating the install script applying the patch.
To do this, do this:
mv html html.modified
cp -a html.orig html
mv html.orig html.pristine
(the last step is to prevent patch from accidentally patching html.orig)
then try your patch against html dir (which is now like the original):
patch -p0 -E < app-patch.diff
Doing this '''will''' save you a lot of trial-and-error in the installer.
== References ==
* Good [http://www.linuxtutorialblog.com/post/introduction-using-diff-and-patch-tutorial reference tutorial on diff and patch]
* [http://stephenjungels.com/jungels.net/articles/diff-patch-ten-minutes.html Ten minute guide to diff and patch]