git show --pretty="format:" --name-only [what] | grep -v 'excludeDir/' | ... more greps | xargs git show [what]

example to exclude symfony generated modella:
    git show --pretty=format: --name-only 1234567 | grep -v "\(om/\|map/\|base/\|form/\|filter/\)" | xargs git show 1234567
    git diff origin/parentBranch --name-only | grep -v "\(om/\|map/\|base/\|form/\|filter/\)" | xargs git diff origin/parentBranch