Answer by Nick Tsai for Remove all files except some from a directory

I prefer to use sub query list:

rm -r `ls | grep -v "textfile.txt\|backup.tar.gz\|script.php\|database.sql\|info.txt"`

-v, --invert-match select non-matching lines

\| Separator

To avoid preserving files with similar names:

rm -r `ls | grep -v "^textfile.txt$\|^backup.tar.gz$"`