Created
April 11, 2015 20:59
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Calculate IPv4 network address and CIDR mask from IP address (dotted quad) and network mask (dotted quad)
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# $1 is a decimal number between 0-255 | |
dec2bin () { | |
[ -z "$1" ] && return | |
D2B=({0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1}{0..1}) | |
echo ${D2B[$1]} | |
} | |
# $1 is ip address (dotted quad) | |
# $2 is netmask (dotted quad) | |
calc_network () { | |
[ -z "$1" ] && return | |
[ -z "$2" ] && return | |
IFS=. read -r i1 i2 i3 i4 <<< "$1" | |
IFS=. read -r m1 m2 m3 m4 <<< "$2" | |
full_mask_bin="$(dec2bin $m1 )$(dec2bin $m2 )$(dec2bin $m3)$(dec2bin $m4)" | |
mask_bin=$(sed -r 's/0*$//' <<< "$full_mask_bin") | |
printf "%d.%d.%d.%d/%s\n" \ | |
"$((i1 & m1))" \ | |
"$((i2 & m2))" \ | |
"$((i3 & m3))" \ | |
"$((i4 & m4))" \ | |
${#mask_bin} | |
} |
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