diff
Compares filenames and lines. Very slow.
/usr/bin/diff -qr /dirA /dirB
comm + find
Only compares filenames. Fast.
comm -3 <(find /dirA -type f -printf "%f\n"|sort) <(find /dirB -type f -printf "%f\n"|sort)
Also works with diff.
diff + find + md5sum
Compares filenames and content. Slow.
/usr/bin/diff <(find /dirA -type f -printf "%p " -exec md5sum '{}' \; | cut -d '/' -f1 | sort) \
<(find /dirB -type f -printf "%p " -exec md5sum '{}' \; | cut -d '/' -f1 | sort)
git
Compares filenames and content. Slow.
git diff -D --no-index /dirA /dirB
Hope this helps.