You can fix it like this also
cd platforms/ios/cordova/lib
sudo chmod +x copy-www-build-step.sh
This basically gives the file execute permission only instead of chmod 777 which gives it full permission (read, write, execute.) For anyone wanting clarification on what the difference is.
与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…