regex - How to invert a grep expression

Question

The following grep expression successfully lists all the .exe and .html files in the current directory and sub directories.

ls -R |grep -E .*[.exe]$|.*[.html]$  

How do I invert this result to list those that aren't a .html or .exe instead. (That is, !=.)

Answer 1

Use command-line option -v or --invert-match,

ls -R |grep -v -E .*[.exe]$|.*[.html]$