For directories:

  find /desired_location -type d -print0 | xargs -0 chmod 0755
  

For files:

  find /desired_location -type f -print0 | xargs -0 chmod 0644

Adapt as required.

   find . -name '*altauserpoints*' -print0 | xargs -0 -P0 rm
   

Adapt as required.

   sed -i 's/foo/bar/g' *
   

To make the change through a whole directory tree:

   find ~/public_html/my_website/pages -type f -exec sed -i 's/2017/2018/g' {} \;