rm !(textfile.txt|backup.tar.gz|script.php|database.sql|info.txt)
The extglob (Extended Pattern Matching) needs to be enabled in BASH (if it's not enabled):
shopt -s extglob
rm !(textfile.txt|backup.tar.gz|script.php|database.sql|info.txt)
The extglob (Extended Pattern Matching) needs to be enabled in BASH (if it's not enabled):
shopt -s extglob