Delete all files in a directory whose name do not match a line in a file list

I realize that any question asking how to delete files must be taken with great care. My first answer was too hasty I didn't take the fact that the filelist could be malformed to be used with egrep. I edited the answer to reduce that risk.

That should work for the files that has no space in the name:

First rebuild your filelist to be sure to match the exact file name:

sed -e 's,^,^,' -e 's,$,$,'  filelist  > newfilelist 

build the rm commands

cd your_directory
ls | egrep -vf newfilelist   | xargs -n 1 echo rm  >  rmscript

Check if the rm script suits you (You can do it with "vim" or "less").
Then perform the action :

sh -x rmscript

If the files have spaces in their name (if the files have the " in the name then this will not work) :

ls | egrep -vf newfilelist  | sed 's,^\(.*\)$,rm "\1",' > rmscript

of course the filelist should not be in the same directory!

EDITED :

The Nathan's file list contained names that were matching all the files in the directory (like "html" matches "bob.html"). So nothing was deleted because egrep -vf absorbed all the stream. I added a command to put a "^" and a "$" around each file name. I was lucky here that Nathan's file list was correct. Would have it been DOS formatted with CR-LF ended lines or with additional spaces, no files would have been preserved by the egrep and all been deleted.