I’ll update this frequently.
Mass replace recursively.
find ./ -type f -exec sed -i 's/string1/string2/g' {} \;
Change all image sizes that are larger than 800×600 to that size.
find . -type f -exec mogrify -resize 800x600 {} \;
Force copy.
/bin/cp -Rf mydomain.backup/* mydomain/public_html/