Anyone know how cksum works? Post: 57453

9 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

cksum all executables on drive

I know I can run the cksum command for multiple files in a directory and send the results to a new file. EX.) # cd /usr # cksum *_ex* > /tmp/cksumusr.txt But I can't figure out how to run this command on multiple files in all directories on drive. Is it possible to do this, without having...

2. UNIX for Dummies Questions & Answers

cksum parts of a file

Every time we build an executable the date and time are put into the file, I need to run checksum on just the working lines.(IE, no header files) Is this even possible, if so how would I go about it? I am using a HP-UX server any help you can give me will be greatly appreciated. Thanks

3. Shell Programming and Scripting

cksum question

Hi there, I have a query about cksum. I'm running a script on the Unix box and in a script the cksum result differs from when I run it manually. As far as I can see the file is not being changed, is there any other times that the cksum would be different.

4. Shell Programming and Scripting

The cksum Problem

Hi, I have a working script, well it works on my machine but when I try it on others the cksum section does not work properly (I know the scripting is not of a high quality but I'm just trying to get it working) Heres the script: #!/bin/sh case $# in 0) echo "usage: enshar filename...

5. Shell Programming and Scripting

using cksum

hi, I am trying to use the cksum feature in unix. when i make a call to it i get returned something along the lines of: 4603435 14 file3 how do i get the first part of this response only; i.e: 4603435 I'm trying to use at a way without the use of sed and creating temp...

6. UNIX for Advanced & Expert Users

Cksum dependencies

Hi, On what factors does the cksum depend. If i build 2 machines exactly the same, then can i get the checksum of 2 compiled files same. Thanks

7. UNIX for Dummies Questions & Answers

sorting cksum output.

Hi guys, I have a service directory with a lot of files in. I have to cksum the whole directory and compare it to a release note document. However the problem I have is the files are listed in different lines when running cksum as they are in the release doc. Therefore cksum shows...

8. Shell Programming and Scripting

EEPROM CKSUM? what is this?

Hi all, So I have a binary file and I need to generate an expected EEPROM checksum for it. Ideally, I would like to input the file (with the path) and output a computed checksum. Ive been using (cksum file1) with no avail and I was just curious as to whether there is such thing as EEPROM cksum,...

9. UNIX for Dummies Questions & Answers

cksum does not give me crc32

Is cksum the right command to calculate the crc32 checksum value? I tried it for a number of files now and every time the results dont match. So there is nothing wrong with the file. Also, cksum gives me an all numerical value while crc32 is alpha numeric. What am I doing wrong? Thanks

LEARN ABOUT SUSE

sum

sum(n)							     Cyclic Redundancy Checks							    sum(n)

__________________________________________________________________________________________________________________________________________________

NAME

       sum - Calculate a sum(1) compatible checksum

SYNOPSIS

       package require Tcl  8.2

       package require sum  ?1.1.0?

       ::crc::sum ?-bsd | -sysv? ?-format fmt? ?-chunksize size? [ -filename file | -channel chan | string ]

_________________________________________________________________

DESCRIPTION

       This  package  provides	a Tcl-only implementation of the sum(1) command which calculates a 16 bit checksum value from the input data.  The
       BSD sum algorithm is used by default but the SysV algorithm is also available.

COMMANDS

       ::crc::sum ?-bsd | -sysv? ?-format fmt? ?-chunksize size? [ -filename file | -channel chan | string ]
	      The command takes string data or a file name or a channel and returns a checksum value calculated using the  sum(1)  algorithm.  The
	      result is formatted using the format(n) specifier provided or as an unsigned integer (%u) by default.

OPTIONS

       -sysv  The SysV algorithm is fairly naive. The byte values are summed and any overflow is discarded. The lowest 16 bits are returned as the
	      checksum.  Input with the same content but different ordering will give the same result.

       -bsd   This algorithm is similar to the SysV version but includes a bit rotation step which provides a dependency on the order of the  data
	      values.

       -filename name
	      Return a checksum for the file contents instead of for parameter data.

       -channel chan
	      Return  a  checksum  for	the  contents  of the specified channel. The channel must be open for reading and should be configured for
	      binary translation. The channel will no be closed on completion.

       -chunksize size
	      Set the block size used when reading data from either files or channels. This value defaults to 4096.

       -format string
	      Return the checksum using an alternative format template.

EXAMPLES

       % crc::sum "Hello, World!"
       37287

       % crc::sum -format 0x%X "Hello, World!"
       0x91A7

       % crc::sum -file sum.tcl
       13392

AUTHORS

       Pat Thoyts

BUGS, IDEAS, FEEDBACK
       This document, and the package it describes, will undoubtedly contain bugs and other problems.  Please report such in the category  crc	of
       the  Tcllib  SF	Trackers [http://sourceforge.net/tracker/?group_id=12883].  Please also report any ideas for enhancements you may have for
       either package and/or documentation.

SEE ALSO

       cksum(n), crc32(n), sum(1)

KEYWORDS

       checksum, cksum, crc, crc32, cyclic redundancy check, data integrity, security, sum

COPYRIGHT

       Copyright (c) 2002, Pat Thoyts <patthoyts@users.sourceforge.net>

crc								       1.1.0								    sum(n)