NAME
cksum — print file checksum and sizes
DESCRIPTION
The
cksum
command calculates and prints to standard output a
checksum for each named file, the number of octets
in the file and the filename.
cksum
uses a portable algorithm based on a 32-bit Cyclic Redundancy
Check.
This algorithm finds a broader spectrum of errors
than the 16-bit algorithms used by
sum
(see
sum(1)).
The CRC is the sum of the following expressions, where
x
is each byte of the file.
x32 +
x26 +
x23 +
x22 +
x16 +
x12 +
x11 +
x10 +
x7 +
x5 +
x4 +
x2 +
x1 +
x0
The results of the calculation are truncated to a 32-bit value.
The number of bytes in the file is also printed.
Standard input is used if no file names are given.
cksum
is typically used to verify data integrity when copying
files between systems.
EXTERNAL INFLUENCES
Environment Variables
LANG
determines the locale to use for the locale categories when both
LC_ALL
and the corresponding environment variable (beginning with
LC_)
do not specify a locale.
If
LANG
is not set or is set to the empty string,
a default of "C" (see
lang(5))
is used.
LC_CTYPE
determines the locale for interpretation of sequences of bytes of text
data as characters (e.g., single- verses multibyte characters in
arguments and input files).
LC_MESSAGES
determines the language in which messages are displayed.
If any internationalization variable
contains an invalid setting,
cksum
behaves as if all internationalization variables are set to "C".
See
environ(5).
RETURN VALUE
Upon completion,
cksum
returns one of the following values:
- 0
All files were processed successfully.
- >0
One or more files could not be read or another error occurred.
If an inaccessible file is encountered,
cksum
continues processing any remaining files,
but the final exit status is affected.
STANDARDS CONFORMANCE
cksum: XPG4, POSIX.2
Printable version
