Using boolean expression Bash script Post: 302966195

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Top Forums Shell Programming and Scripting Using boolean expression Bash script Post 302966195 by Miron on Tuesday 9th of February 2016 08:44:17 AM

02-09-2016

Registered User

Using boolean expression Bash script

Hi,
Im trying to write a Bash script that calculates the least common subnet for two address.

Theoretical: I have to change IP from decimal to binary, then apply XNOR on the two IPs.

I tried to write this:

Code:

#!/bin/bash
echo "Ebter the first ip"
read ip1
echo "Enter the second ip"
read ip2 

#Separate octs of first ip  

a1=`echo $ip1 | awk 'BEGIN{FS="."}{print $1}'`
a2=`echo $ip1 | awk 'BEGIN{FS="."}{print $2}'`
a3=`echo $ip1 | awk 'BEGIN{FS="."}{print $3}'`
a4=`echo $ip1 | awk 'BEGIN{FS="."}{print $4}'`  
#convert decimal to binary

b1=`echo "obase=2;$a1" | bc`
b2=`echo "obase=2;$a2" | bc`
b3=`echo "obase=2;$a3" | bc`
b4=`echo "obase=2;$a4" | bc`  

#Separate octs of second ip

c1=`echo $ip2 | awk 'BEGIN{FS="."}{print $1}'`
c2=`echo $ip2 | awk 'BEGIN{FS="."}{print $2}'`
c3=`echo $ip2 | awk 'BEGIN{FS="."}{print $3}'`
c4=`echo $ip2 | awk 'BEGIN{FS="."}{print $4}'`  

#convert decimal to binary (second IP)

d1=`echo "obase=2;$c1" | bc`
d2=`echo "obase=2;$c2" | bc`
d3=`echo "obase=2;$c3" | bc`
d4=`echo "obase=2;$c4" | bc`

e1=`echo $b1 || $d1 | rev`
e2=`echo $b2 || $d2 | rev`
e3=`echo $b3 || $d3 | rev`
e4=`echo $b4 || $d4 | rev`

echo "$e1.$e2.$e3.$e4"

I have two problems:
I need to apply XNOR to the binary IP (bit by bit), but if the result of a specific bit becomes zero I want to stop the operation and make another bit that follows the zero, zero also.
I need that XNOR ignores "."

Can someone help me with this issue please?

Moderator's Comments:

Please use code tags next time for your code and data, thanks

Last edited by Miron; 02-09-2016 at 10:43 AM.. Reason: code tags

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bashbug

BASHBUG(1)							      bashbug								BASHBUG(1)

NAME

       bashbug - report a bug in bash

SYNOPSIS

       bashbug [--help] [--version] [bug-report-email-addresses]

DESCRIPTION

       bashbug is a utility for reporting bugs in Bash to the maintainers.

       bashbug will start up your preferred editor with a preformatted bug report template for you to fill in. Save the file and quit the editor
       once you have completed the missing fields.  bashbug will notify you of any problems with the report and ask for confirmation before
       sending it. By default the bug report is mailed to both the GNU developers and the Debian Bash maintainers. The recipients can be changed
       by giving a comma separated list of bug-report-email-addresses.

       If you invoke bashbug by accident, just quit your editor. You will always be asked for confirmation before a bug report is sent.

OPTIONS

       --help
	      Show a brief usage message and exit.

       --version
	      Show the version of bashbug and exit.

       bug-report-email-addresses
	      Comma separated list of recipients' email addresses. By default the report is mailed to both the GNU developers and the Debian Bash
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ENVIRONMENT

       DEFEDITOR
	      Editor to use for editing the bug report.

       EDITOR
	      Editor to use for editing the bug report (overridden by DEFEDITOR).

SEE ALSO

       bash(1), reportbug(1), update-alternatives(8) for preferred editor.

AUTHOR

       This manual page was written by Christer Andersson <klamm@comhem.se> for the Debian project (but may be used by others).

GNU Bash 3.1							 11 December 2007							BASHBUG(1)