tag:
type: txt
help: interface name
syntax:expression: exec " \
        if [ -z \"`ip link | grep $VAR(@)`\" ]; then \
          echo Invalid interface [$VAR(@)]; \
          exit 1 ; \
        fi ; "
allowed: for dev in /sys/class/net/*; 
         do if [[ ! $dev =~ "net/lo" ]]; then
            echo -n ${dev##*/} " "
            fi
         done
