tr(C)                           19 June 1992                           tr(C)


 Name

    tr - translate characters

 Syntax

    tr [ -cds ] [ string1 [ string2 ] ]

 Description

    The tr command copies the standard input to the standard output with sub-
    stitution or deletion of selected characters.  Input characters found in
    string1 are mapped into the corresponding characters of string2.  Any
    combination of the options -cds may be used:

    -c      Complements the set of characters in string1 with respect to the
            universe of characters whose ASCII codes are 001 through 377
            octal

    -d      Deletes all input characters in string1

    -s      Squeezes all strings of repeated output characters that are in
            string2 to single characters

    The following abbreviation conventions may be used to introduce ranges of
    characters or repeated characters into the strings:

    [a-z]   Stands for the string of characters whose ASCII codes run from
            character ``a'' to character ``z'', inclusive.

    [a*n]   Stands for n repetitions of a.  If the first digit of n is 0, n
            is considered octal; otherwise, n is taken to be decimal.  A zero
            or missing n is taken to be huge; this facility is useful for
            padding string2.

    The escape character ``\'' may be used as in the shell to remove special
    meaning from any character in a string.  In addition, ``\'' followed by
    1, 2, or 3 octal digits, stands for the character whose ASCII code is
    given by those digits.

    The following example creates a list of all the words in file1, one per
    line in file2, where a word is taken to be a maximal string of alphabet-
    ics.  The strings are quoted to protect the special characters from
    interpretation by the shell; 012 is the ASCII code for newline:

       tr -cs "[A-Z][a-z]" "[\012*]" <file1 >file2


 See also

    ascii(M), ed(C), sh(C)

 Notes

    tr will not handle ASCII NUL in string1 or string2; it always deletes NUL
    from the input.

 Standards conformance

    tr is conformant with:

    AT&T SVID Issue 2;
    and X/Open Portability Guide, Issue 3, 1989.