To recursive change all the directories to 755 (drwxr-xr-x)
<code>
find . -type d -exec chmod 755 {} \;
</code>

Similarly to recursive change all the files to 644 (-rw-r--r--)
<code>
find . -type f -exec chmod 644 {} \;
</code>

Note: {} is replaced by the file path and the semicolon must be escaped..