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 corresponding 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\f1, where x is any character (possibly quoted), stands for a range of characters: a possibly empty sequence of codes running from the successor of the previous code up through the code for x . The character .L \e followed by 1, 2 or 3 octal digits stands for the character whose 16-bit value is given by those digits. The character sequence .L \ex followed by 1 to 6 hexadecimal digits stands for the character whose 21-bit value is given by those digits. A .L \e followed by any other character stands for that character.

Replace all upper-case ASCII letters by lower-case. .EX tr A-Z a-z <mixed >lower

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

.EX tr -cs A-Za-z ' ' <file1 >file2 /appl/cmd/tr.b