Get diff changes between original files installed with apt and current files

Reference: https://unix.stackexchange.com/questions/72746/get-diff-changes-between-original-files-installed-with-apt-and-current-files

exit on failure

set -e

package=php5-fpm
mkdir $package
cd $package

you could also get the file from a package mirror if you have an older version of apt-get that doesn't support 'download' or if you would like more control over what package version you are downloading. (e.g. http://archive.ubuntu.com/ubuntu/pool/main/)

apt-get download $package

deb package files are ar archives

ar vx ${package}*.deb

containing some compressed tar archives

tar xf data.tar.gz

now you have the files

you can get diffs for all of the files in etc if you would like

find etc -type f |
while read file ; do
   diff $file /$file
done