sort a text file, then see how many lines are unique:
sort myfile.txt | uniq -u | wc -l (count the number of unique entries in a file) sort myfile.txt | uniq -d | wc -l (count the number of lines that are duplicates in a file) sort myfile.txt | uniq -dc (display the number of duplicates for each line in a file)
tr "[:upper:]" "[:lower:]" < myfile.txt | sort (translate all of the uppercase letters to lowercase)
tr "[:upper:]" "[:lower:]" < myfile.txt | sort | uniq -u > unique-sorted-lowercase-myfile.txt