toggle_network-interface_up-down.bash

toggle_network-interface_up-down.bash

#!/bin/bash

if (( $# < 1 ))
then
  script_name=`basename $0`
  echo "Usage: $script_name <interface_name>"
  echo "  e.g.: $script_name `ifconfig -l -d | cut -f 1 -d ' '`"
  exit
fi

interface=$1

# For grep:
# Normally, exit  status is 0 if selected lines are found and 1 otherwise.  But the exit status is 2 if an error occurred, unless the -q or --quiet or --silent option is used and a selected line is found.

if ( ifconfig -l -u | grep $interface > /dev/null )
then
  sudo ifconfig $interface down
elif ( ifconfig -l -d | grep $interface > /dev/null )
then
  sudo ifconfig $interface up
fi