diff to output only the file names

From the diff man page:

-q   Report only whether the files differ, not the details of the differences.
-r   When comparing directories, recursively compare any subdirectories found.

Example command:

diff -qr dir1 dir2

Example output (depends on locale):

$ ls dir1 dir2dir1:same-file  different  only-1dir2:same-file  different  only-2$ diff -qr dir1 dir2Files dir1/different and dir2/different differOnly in dir1: only-1Only in dir2: only-2

You can also use rsync

rsync -rv --size-only --dry-run /my/source/ /my/dest/ > diff.out

If you want to get a list of files that are only in one directory and not their sub directories and only their file names:

diff -q /dir1 /dir2 | grep /dir1 | grep -E "^Only in*" | sed -n 's/[^:]*: //p'

If you want to recursively list all the files and directories that are different with their full paths:

diff -rq /dir1 /dir2 | grep -E "^Only in /dir1*" | sed -n 's/://p' | awk '{print $3"/"$4}'

This way you can apply different commands to all the files.

For example I could remove all the files and directories that are in dir1 but not dir2:

diff -rq /dir1 /dir2 | grep -E "^Only in /dir1*" | sed -n 's/://p' | awk '{print $3"/"$4}' xargs -I {} rm -r {}