# sum(n) 1.0 crc "sum"

## NAME

sum - calculate a sum(1) compatible checksum

## SYNOPSIS

package require Tcl 8.2
package require sum ?1.0?

::crc::sum ?-format format? message
::crc::sum ?-format format? -filename file

## DESCRIPTION

This package provides a Tcl-only implementation of the sum(1) command which calculates a 16 bit checksum value from the input data. The BSD sum algorithm is used by default but the SysV algorithm is also available.

## COMMANDS

::crc::sum ?-format format? message
::crc::sum ?-format format? -filename file
  The command takes string data or a file name and returns a checksum value calculated using the sum(1) algorithm. The result is formatted using the format(n) specifier provided or as an unsigned integer (%u) by default.

## OPTIONS

-filename name
  Return a checksum for the file contents instead of for parameter data.
-format string
  Return the checksum using an alternative format template.

## EXAMPLES

    % crc::sum "Hello, World!"
    37287

    % crc::sum -format 0x%X "Hello, World!"
    0x91A7

    % crc::sum -file sum.tcl
    13392

## SEE ALSO

sum(1), cksum(n), crc32(n)

## AUTHORS

Pat Thoyts

## KEYWORDS

sum, cksum, checksum, crc, crc32, cyclic redundancy check, data integrity, security