private_dot_config/i3blocks/iface/executable_iface

#!/usr/bin/env bash
# Copyright (C) 2014 Julien Bonjean <julien@bonjean.info>
# Copyright (C) 2014 Alexander Keller <github@nycroth.com>

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

#------------------------------------------------------------------------

# Use the provided interface, otherwise the device used for the default route.
IF="${IFACE:-$BLOCK_INSTANCE}"
IF="${IF:-$(ip route | awk '/^default/ { print $5 ; exit }')}"

# Exit if there is no default route
[[ -z "$IF" ]] && exit

#------------------------------------------------------------------------

# As per #36 -- It is transparent: e.g. if the machine has no battery or wireless
# connection (think desktop), the corresponding block should not be displayed.
[[ ! -d /sys/class/net/${IF} ]] && exit

#------------------------------------------------------------------------

AF=${ADDRESS_FAMILY:-inet6?}
LABEL="${LABEL:-}"

for flag in "$1" "$2"; do
  case "$flag" in
    -4)
      AF=inet ;;
    -6)
      AF=inet6 ;;
    -L)
      if [[ "$IF" = "" ]]; then
        LABEL="iface"
      else
        LABEL="$IF:"
      fi ;;
  esac
done

if [[ "$IF" = "" ]] || [[ "$(cat /sys/class/net/$IF/operstate)" = 'down' ]]; then
  echo "${LABEL} down" # full text
  echo "${LABEL} down" # short text
  echo \#FF0000 # color
  exit
fi

# if no interface is found, use the first device with a global scope
IPADDR=$(ip addr show $IF | perl -n -e "/$AF ([^ \/]+).* scope global/ && print \$1 and exit")

case $BLOCK_BUTTON in
  3) echo -n "$IPADDR" | xclip -q -se c ;;
esac

if [[ "${display_wifi_name}" == "1" ]];
then
  # try to guess the wifi name
  if command -v iw > /dev/null && iw $IF info > /dev/null 2>&1;
  then
    WIFI_NAME=$(iw $IF info | grep -Po '(?<=ssid ).*' | tr -d " \t\n\r")

    if [[ $BLOCK_BUTTON -eq 1 ]];
    then
      message="$LABEL $WIFI_NAME ($IPADDR)"
    else
      message="$LABEL $WIFI_NAME"
    fi
  else
    message="$LABEL $IPADDR"
  fi
else
  message="$LABEL $IPADDR"
fi

#------------------------------------------------------------------------

echo "$message"