C:\>perldoc -f printf
    printf FILEHANDLE FORMAT, LIST
    printf FILEHANDLE
    printf FORMAT, LIST
    printf  Equivalent to "print FILEHANDLE sprintf(FORMAT, LIST)", except
            that $\ (the output record separator) is not appended. The first
            argument of the list will be interpreted as the "printf" format.
            See "sprintf" for an explanation of the format argument. If you
            omit the LIST, $_ is used; to use FILEHANDLE without a LIST, you
            must use a real filehandle like "FH", not an indirect one like
            $fh. If "use locale" is in effect and POSIX::setlocale() has
            been called, the character used for the decimal separator in
            formatted floating-point numbers is affected by the LC_NUMERIC
            locale setting. See perllocale and POSIX.

            Don't fall into the trap of using a "printf" when a simple
            "print" would do. The "print" is more efficient and less error
            prone.