Using boolean expression Bash script


 
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# 8  
Old 02-12-2016
Ooohh - you're after the netmask. Try
Code:
{ read IP1; read IP2; } < file1
BIP1=$(( 0x$(printf "%02X" ${IP1//./ })))
BIP2=$(( 0x$(printf "%02X" ${IP2//./ })))
TMP=$(( BIP1 ^ BIP2 ))
I=1
while [ $(( I*=2 )) -lt $TMP ]; do :; done                           
I=$(( --I ^ 2**32-1 ))
printf "%d.%d.%d.%d\n" $((I>>24)) $((I>>16&255)) $((I>>8&255)) $((I&255))
255.255.224.0

---------- Post updated at 14:30 ---------- Previous update was at 14:13 ----------

or
Code:
{ read IP1; read IP2; } < file1
BIP1=$(( 0x$(printf "%02X" ${IP1//./ })))
BIP2=$(( 0x$(printf "%02X" ${IP2//./ })))
TMP=$(( BIP1 ^ BIP2 ))   
while (( TMP )); do TMP=$((TMP>>1)); ((I++)); done
I=$((2**32-1 ^ 2**I-1))
printf "%d.%d.%d.%d\n" $((I>>24)) $((I>>16&255)) $((I>>8&255)) $((I&255))

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ATF-SH(1)						    BSD General Commands Manual 						 ATF-SH(1)

NAME
atf-sh [-s shell] -- interpreter for shell-based test programs SYNOPSIS
atf-sh script DESCRIPTION
atf-sh is an interpreter that runs the test program given in script after loading the atf-sh(3) library. atf-sh is not a real interpreter though: it is just a wrapper around the system-wide shell defined by ATF_SHELL. atf-sh executes the inter- preter, loads the atf-sh(3) library and then runs the script. You must consider atf-sh to be a POSIX shell by default and thus should not use any non-standard extensions. The following options are available: -s shell Specifies the shell to use instead of the value provided by ATF_SHELL. ENVIRONMENT
ATF_LIBEXECDIR Overrides the builtin directory where atf-sh is located. Should not be overridden other than for testing purposes. ATF_PKGDATADIR Overrides the builtin directory where libatf-sh.subr is located. Should not be overridden other than for testing purposes. ATF_SHELL Path to the system shell to be used in the generated scripts. Scripts must not rely on this variable being set to select a specific interpreter. EXAMPLES
Scripts using atf-sh(3) should start with: #! /usr/bin/env atf-sh Alternatively, if you want to explicitly choose a shell interpreter, you cannot rely on env(1) to find atf-sh. Instead, you have to hardcode the path to atf-sh in the script and then use the -s option afterwards as a single parameter: #! /path/to/bin/atf-sh -s/bin/bash ENVIRONMENT
ATF_SHELL Path to the system shell to be used in the generated scripts. SEE ALSO
atf-sh(3) BSD
September 27, 2014 BSD