break out special local mail processing (e.g., mapping to the

[unix-history] / usr / src / usr.bin / cksum / cksum.1

diff --git a/usr/src/usr.bin/cksum/cksum.1 b/usr/src/usr.bin/cksum/cksum.1
index e051bc4..69ba07f 100644 (file)
--- a/usr/src/usr.bin/cksum/cksum.1
+++ b/usr/src/usr.bin/cksum/cksum.1
@@ -1,13 +1,16 @@
-.\" Copyright (c) 1991, 1991 The Regents of the University of California.
-.\" All rights reserved.
+.\" Copyright (c) 1991, 1993
+.\"    The Regents of the University of California.  All rights reserved.
+.\"
+.\" This code is derived from software contributed to Berkeley by
+.\" the Institute of Electrical and Electronics Engineers, Inc.

 .\"
 .\" %sccs.include.redist.roff%
 .\"
 .\"
 .\" %sccs.include.redist.roff%
 .\"

-.\"    @(#)cksum.1     5.4 (Berkeley) %G%
+.\"    @(#)cksum.1     8.1 (Berkeley) %G%

 .\"
 .Dd 
 .Dt CKSUM 1
 .\"
 .Dd 
 .Dt CKSUM 1

-.Os
+.Os BSD 4.4

 .Sh NAME
 .Nm cksum
 .Nd display file checksums and block counts
 .Sh NAME
 .Nm cksum
 .Nd display file checksums and block counts


@@ -18,12 +21,13 @@
 .Sh DESCRIPTION
 The
 .Nm cksum
 .Sh DESCRIPTION
 The
 .Nm cksum

-utility writes to standard output three whitespace separated fields for each
-input file (or the standard input by default).
+utility writes to the standard output three whitespace separated
+fields for each input file.

 These fields are a checksum
 .Tn CRC ,
 These fields are a checksum
 .Tn CRC ,

-the total number of bytes in the file and
-the file name.
+the total number of octets in the file and the file name.
+If no file name is specified, the standard input is used and no file name
+is written.

 .Pp
 The options are as follows:
 .Bl -tag -width indent
 .Pp
 The options are as follows:
 .Bl -tag -width indent


@@ -57,7 +61,7 @@ r = s % 2^16 + (s % 2^32) / 2^16;
 cksum = (r % 2^16) + r / 2^16;
 .Ed
 .Pp
 cksum = (r % 2^16) + r / 2^16;
 .Ed
 .Pp

-Both algorithm 1 and 2 write to standard output the same fields as
+Both algorithm 1 and 2 write to the standard output the same fields as

 the default algorithm except that the size of the file in bytes is
 replaced with the size of the file in blocks.
 For historic reasons, the block size is 1024 for algorithm 1 and 512
 the default algorithm except that the size of the file in bytes is
 replaced with the size of the file in blocks.
 For historic reasons, the block size is 1024 for algorithm 1 and 512


@@ -88,30 +92,35 @@ the following procedure:
 .Bd -filled -offset indent
 The
 .Ar n
 .Bd -filled -offset indent
 The
 .Ar n

-bits of the file are considered to be the coefficients of a mod 2
+bits to be evaluated are considered to be the coefficients of a mod 2

 polynomial M(x) of degree
 .Ar n Ns \-1 .
 polynomial M(x) of degree
 .Ar n Ns \-1 .

+These
+.Ar n
+bits are the bits from the file, with the most significant bit being the most
+significant bit of the first octet of the file and the last bit being the least
+significant bit of the last octet, padded with zero bits (if necessary) to
+achieve an integral number of octets, followed by one or more octets
+representing the length of the file as a binary value, least significant octet
+first.
+The smallest number of octets capable of representing this integer are used.

 .Pp
 M(x) is multiplied by x^32 (i.e., shifted left 32 bits) and divided by
 G(x) using mod 2 division, producing a remainder R(x) of degree <= 31.
 .Pp
 M(x) is multiplied by x^32 (i.e., shifted left 32 bits) and divided by
 G(x) using mod 2 division, producing a remainder R(x) of degree <= 31.

-During the division, each time the intermediate remainder is zero, it
-is changed to the next value from a predefined sequence of
-32-bit integers before completing the division.
-This sequence is long and complex -- see the source code for more
-information.

 .Pp
 The coefficients of R(x) are considered to be a 32-bit sequence.
 .Pp
 The coefficients of R(x) are considered to be a 32-bit sequence.

-.Ed

 .Pp
 .Pp

-The calculation used is identical to that given in pseudo-code in
-the
-.Tn ACM
-article referenced below.
+The bit sequence is complemented and the result is the CRC.
+.Ed

 .Pp
 The
 .Nm cksum
 utility exits 0 on success, and >0 if an error occurs.
 .Sh SEE ALSO
 .Pp
 The
 .Nm cksum
 utility exits 0 on success, and >0 if an error occurs.
 .Sh SEE ALSO

+The default calculation is identical to that given in pseudo-code
+in the following
+.Tn ACM
+article.

 .Rs
 .%T "Computation of Cyclic Redundancy Checks Via Table Lookup"
 .%A Dilip V. Sarwate
 .Rs
 .%T "Computation of Cyclic Redundancy Checks Via Table Lookup"
 .%A Dilip V. Sarwate


@@ -119,11 +128,11 @@ utility exits 0 on success, and >0 if an error occurs.
 .%D "August 1988"
 .Re
 .Sh STANDARDS
 .%D "August 1988"
 .Re
 .Sh STANDARDS

-.Nm Cksum
-is expected to conform to
-.St -p1003.2 .
+The
+.Nm cksum
+utility is expected to be POSIX 1003.2 compatible.

 .Sh HISTORY
 The
 .Nm cksum
 .Sh HISTORY
 The
 .Nm cksum

-utility is
-.Ud .
+utility appears in
+.Bx 4.4 .