Initial commit

snippets/cidr2mask.sh

@@ -0,0 +1,32 @@
+#!/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
+
+