tr <string1> [string2]
|Complement the set of characters in string1, that is '-C ab' includes every character except for 'a' and 'b'
|Same as '-C' but complement the set of values in string1
|Delete characters in string1 from the input
|Squeeze multiple occurrences of the characters listed in the last operand (either string1 or string2) in the input into a single instance of the character. This occurs after all deletion and translation is completed
|Guarantee that any output is unbuffered