tr(1posix) - translate characters
-c     Complement the set of values specified by string1. See the EXTENDED DESCRIPTION section.
-C     Complement the set of characters specified by string1. See the EXTENDED DESCRIPTION section.
-d     Delete all occurrences of input characters that are specified by string1.
-s     Replace instances of repeated characters with a single character, as  described  in  the  EXTENDED
       DESCRIPTION section.