sum - Displays the checksum and block count of a file
sum [-o|-r] [file...]
and calculates a 16-bit checksum and the number of blocks in the file.
argument is omitted,
reads standard input.
Interfaces documented on this reference page conform to industry standards as follows:
sum: XPG4, XPG4-UNIX
Refer to the
reference page for more information
about industry standards and associated tags.
[Compaq] Uses an algorithm to compute the checksum using
Uses an alternate algorithm to compute the checksum (rigorous
byte-by-byte computation rather than the word-by-word computation). 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
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
the space used in 512-byte units.
[Compaq] The root of the directory tree that contains the commands modified for SVID 2 compliance is specified in the file /etc/svid2_path. You can use /etc/svid2_profile as the basis for, or to include in, your .profile. The file /etc/svid2_profile reads /etc/svid2_path and sets the first entries in the PATH environment variable so that the modified SVID 2 commands are found first.
[Compaq] The checksum algorithms for the default
command and the SVID 2 compliant
command are reversed.
The SVID 2 compliant
command uses the word-by-word
algorithm by default and uses the byte-by-byte algorithm if you specify the
option on the command line.
[Compaq] 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
The following exit values are returned:
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
The following environment variables affect the execution of
Provides a default value for the internationalization variables
that are unset or null. If
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
Commands: cksum(1), wc(1)