Environment variables for ipupdown hook routines

This article details the environment variables being available to the hook routines of ipupdown tool suite which covers ifup and ifdown.

interfaces command shell environment variable name description
(any) ADDRFAM protocol family (inet or inet6)
(any) IFACE name of netdev
(any) LOGICAL formal name of interface
(any) MAIL for e-mail alerting
(any) METHOD static or manual
(any) MODE start
(any) OLDPWD /etc/network
(any) PWD /etc/network/if-up.d
(any) PHASE up or down
(any) SHELL /bin/bash
ethernet-wol IF_ETHERNMET_WOL
ip-forward IP_FORWARD