bash/snippets/cidr2mask.sh
2018-04-30 02:53:44 +02:00

33 lines
488 B
Bash
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#!/usr/bin/env bash
# - Convert CIDR to netmask
# -
cidr2mask() {
local i mask=""
local full_octets=$(($1/8))
local partial_octet=$(($1%8))
for ((i=0;i<4;i+=1)); do
if [ $i -lt $full_octets ]; then
mask+=255
elif [ $i -eq $full_octets ]; then
mask+=$((256 - 2**(8-$partial_octet)))
else
mask+=0
fi
test $i -lt 3 && mask+=.
done
echo $mask
}
cidr=$1
mask=$(cidr2mask $cidr)
echo ""
echo "cidr: $cidr - mask: $mask"
echo ""
exit 0