Create a file called let.txt containing the list of names of files in $/$course$/$linuxgym$/$emptystuff which have lines BEGINNING with the string Let Ensure there is one file name per line $($WITH FULL PATH NAME$).$ Also sort the names in ALPHABETICAL ORDER, remove all extra blank lines and make sure there are NO REPETITIONS of a file name $($ie: file names occurs only once$).$ Each line should be of the form :

$/$course$/$linuxgym$/$emptystuff$/$some$\_$file$\_$name

With no additional detail.