Bitwise negation Post: 302117646

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Top Forums Shell Programming and Scripting Bitwise negation Post 302117646 by dLloydm on Tuesday 15th of May 2007 08:05:21 PM

05-15-2007

Registered User

Bitwise negation

I am taking an online course on Unix scripting. The topic is Unix arithmetic operators and the lesson is Logical and bitwise operations. It is not clear how much storage space Unix uses to represent integers that are typed. Bitwise negation caused me to question how many bits are used to represent numbers.

The course gives an example: ((~ 2#1001)) evaluates to 2#110

This would imply that only 4 bits are used, otherwise I would expect the example to evaluate to 2#11110110 if 8 bits were used an so on.

I do not have access to a Unix OS or this would be easy to check. I don't know if the shell matters, but I would assume BASH since it allows integers.

So, how many bits are use to represent such values? I understand Unix represents everything as strings unless declared as integer such as using typeset -i. Is this the same using something like 2#1111?

Thanks for any help...

dLloydm

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fusioninventory::agent::tools::unix

FusionInventory::Agent::Tools::Unix(3pm)		User Contributed Perl Documentation		  FusionInventory::Agent::Tools::Unix(3pm)

NAME

       FusionInventory::Agent::Tools::Unix - Unix-specific generic functions

DESCRIPTION

       This module provides some Unix-specific generic functions.

FUNCTIONS

   getDeviceCapacity(%params)
       Returns storage capacity of given device, using fdisk.

       Availables parameters:

       logger a logger object
       device the device to use

   getIpDhcp
       Returns an hashref of information for current DHCP lease.

   getFilesystemsFromDf(%params)
       Returns a list of filesystems as a list of hashref, by parsing given df command output.

       logger a logger object
       command the exact command to use
       file the file to use, as an alternative to the command

   getFilesystemsTypesFromMount(%params)
       Returns a list of used filesystems types, by parsing given mount command output.

       logger a logger object
       command the exact command to use
       file the file to use, as an alternative to the command

   getProcessesFromPs(%params)
       Returns a list of processes as a list of hashref, by parsing given ps command output.

       logger a logger object
       command the exact command to use
       file the file to use, as an alternative to the command

   getRoutingTable
       Returns the routing table as an hashref, by parsing netstat command output.

       logger a logger object
       command the exact command to use (default: netstat -nr -f inet)
       file the file to use, as an alternative to the command

perl v5.14.2							    2012-06-25				  FusionInventory::Agent::Tools::Unix(3pm)