TR(1)                                                       TR(1)

          tr - translate characters

          tr [ -cds ] [ string1 [ string2 ] ]

          Tr copies the standard input to the standard output with
          substitution or deletion of selected characters (runes).
          Input characters found in string1 are mapped into the corre-
          sponding characters of string2. When string2 is short it is
          padded to the length of string1 by duplicating its last
          character.  Any combination of the options -cds may be used:

          -c   Complement string1: replace it with a lexicographically
               ordered list of all other characters.

          -d   Delete from input all characters in string1.

          -s   Squeeze repeated output characters that occur in
               string2 to single characters.

          In either string a noninitial sequence -x, where x is any
          character (possibly quoted), stands for a range of charac-
          ters: a possibly empty sequence of codes running from the
          successor of the previous code up through the code for x.
          The character `\' followed by 1, 2 or 3 octal digits stands
          for the character whose 16-bit value is given by those dig-
          its.  The character sequence `\x' followed by 1, 2, 3, or 4
          hexadecimal digits stands for the character whose 16-bit
          value is given by those digits.  A `\' followed by any other
          character stands for that character.

          Replace all upper-case ASCII letters by lower-case.

               tr A-Z a-z <mixed >lower

          Create a list of all the words in `file1' one per line in
          `file2', where a word is taken to be a maximal string of
          alphabetics.  String2 is given as a quoted newline.

               tr -cs A-Za-z '
               ' <file1 >file2