+##finds subnet of ip and netmask
+##params: ip, netmask
+function find_subnet {
+ IFS=. read -r i1 i2 i3 i4 <<< "$1"
+ IFS=. read -r m1 m2 m3 m4 <<< "$2"
+ printf "%d.%d.%d.%d\n" "$((i1 & m1))" "$((i2 & m2))" "$((i3 & m3))" "$((i4 & m4))"
+}
+
+##finds netmask of interface
+##params: interface
+##returns long format 255.255.x.x
+function find_netmask {
+ ifconfig $1 | grep -Eo 'netmask\s+[\.0-9]+' | awk '{print $2}'
+}
+
+##finds short netmask of interface
+##params: interface
+##returns short format, ex: /21
+function find_short_netmask {
+ echo "/$(ip addr show $1 | grep -Eo '^\s+inet\s+[\/\.0-9]+' | awk '{print $2}' | cut -d / -f2)"
+}
+