sum - Displays the checksum and byte count in block-size (1024) units of a
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 input.
Interfaces documented on this reference page conform to industry standards
Refer to the standards(5) reference page for more information about indus-
try standards and associated tags.
-o [Tru64 UNIX] Uses an algorithm to compute the checksum using word-by-
-r 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 commun-
icated 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 compu-
tation by default.
System V Compatibility
[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.
1. [Tru64 UNIX] The default algorithm is no longer the word-by-word com-
putation algorithm. It was changed to the 4.3BSD default algorithm.
2. 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:
0 Successful completion.
>>0 An error occurred.
To display the checksum of datafile and the number of blocks in this file,
If the checksum of datafile is 1605 and if the file contains 3 blocks, sum
1605 3 datafile
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 multi-
byte characters in arguments).
Determines the locale for the format and contents of diagnostic mes-
sages written to standard error.
Determines the location of message catalogues for the processing of
Commands: cksum(1), wc(1)