Nautilus – How to Diff Two Files with Nautilus

You can use a shell loop that runs diff for each file, though this will not catch the cases where d2 contains a file, but d1 doesn't. It might be sufficient though.

for file in d1/*.cpp; do
    diff "$file" "d2/${file##*/}"
done

Or all on one line:

for file in d1/*.cpp; do diff "$file" "d2/${file##*/}"; done

The ${file##*/} part is a special parameter expansion.

If the file variable contains d1/hello.cpp, then "${file##*/}" will expand to hello.cpp (the value of file, but with everything up to, and including, the last / removed).

So "d2/${file##*/}" will result in d2/hello.cpp and the resulting diff command is thus diff d1/hello.cpp d2/hello.cpp

See http://mywiki.wooledge.org/BashFAQ/100 for more on string manipulations in bash.

On a side note, a version control system (such as subversion, git, mercurial etc...) would make this type of diffing much easier.

You can use the original format that creates the huge diff file which you can subsequently split into the small files. You might be interested in csplit for the splitting, or you can use a scripting language like Perl:

perl -ne 'if(/^diff -drupN (.*) (.*)/) {
              my $f = $1;
              $f =~ s{/}{_}g;
              open $FH, ">", "$f.patch" or die $!;
          } else {
              print {$FH} $_;
          }' kernel.patch

If you need the diff line in each file, add the print after the open.