sum - Displays the checksum and byte count in block-size
(1024) units of a file
sum [-o | -r] [file...]
The sum command reads file and calculates a 16-bit checksum
and the byte count in block-size (1024) units in the
file. If the file argument is omitted, sum reads standard
Interfaces documented on this reference page conform to
industry standards as follows:
Refer to the standards(5) reference page for more information
about industry standards and associated tags.
[Tru64 UNIX] Uses an algorithm to compute the checksum
using word-by-word computation. Uses an alternate algorithm
to compute the checksum (rigorous byte-by-byte computation
rather than the word-by-word computation).
[Tru64 UNIX] This is the default.
The file for which a checksum is to be computed. If this
operand is omitted, standard input is used.
The checksum and number of blocks are written to standard
output. The sum command is generally used to determine if
a file that was copied or communicated over transmission
lines is an exact copy of the original. The sum command
writes the space used in 1024-byte units.
[Tru64 UNIX] The checksum is calculated using a rigorous
byte-byte computation by default.
System V Compatibility [Toc] [Back]
[Tru64 UNIX] The checksum algorithms for the default sum
command and the SVID 2 compliant sum command are reversed.
The SVID 2 compliant sum command uses the word-by-word
algorithm by default and uses the byte-by-byte algorithm
if you specify the -r option on the command line.
The sum utility is marked LEGACY in XCU Issue 5. [Tru64
UNIX] The default algorithm is no longer the word-by-word
computation algorithm. It was changed to the 4.3BSD
default algorithm. The algorithms used may not be
portable, that is, the same checksum may not be produced
for the same input on different systems. Portable applications
should use cksum.
The following exit values are returned: Successful completion.
An error occurred.
To display the checksum of datafile and the number of
blocks in this file, enter: sum datafile
If the checksum of datafile is 1605 and if the file contains
3 blocks, sum displays: 1605 3 datafile
ENVIRONMENT VARIABLES [Toc] [Back]
The following environment variables affect the execution
of sum: Provides a default value for the internationalization
variables that are unset or null. If LANG is unset or
null, the corresponding value from the default locale is
used. If any of the internationalization variables contain
an invalid setting, the utility behaves as if none of the
variables had been defined. If set to a non-empty string
value, overrides the values of all the other internationalization
variables. Determines the locale for the interpretation
of sequences of bytes of text data as characters
(for example, single-byte as opposed to multibyte characters
in arguments). Determines the locale for the format
and contents of diagnostic messages written to standard
error. Determines the location of message catalogues for
the processing of LC_MESSAGES.
Commands: cksum(1), wc(1)
[ Back ]