'exists' is used to find out if a hash key exists, this is needed because perl will create a key/value pair even if you are just 'seeing if it's there'. (e.g, its not use on scalars as such) also, the -e (and friends) flags are file test operators where parameter is the name of a file. if (-e /mnt/dos/command.com) { print "good choice, show who's in charge\n"; } see 'perldoc perlfunc' for a list of the file tests you can perform.