fix-etc-resolv.conf-wsl.sh

#!/bin/bash -e
###
### * Save this script and make it executable:
###   1. Put the script to your filesystem into this filepath:
###      - /usr/local/bin/fix-etc-resolv.conf-wsl.sh
###   2. Make it excecutable using:
###      - sudo chmod a+x /usr/local/bin/fix-etc-resolv.conf-wsl.sh
###
### * Allow the script to be run as root without providing a password using:
###   1. Run:
###      - sudo visudo -f /etc/sudoers.d/42-lopin_fix-etc-resolv-conf-wsl
###   2. Paste line:
###      - ALL	ALL=(ALL:ALL)	NOPASSWD:/usr/local/bin/fix-etc-resolv.conf-wsl.sh
###   3. Save & exit
###
### * Make the script to run automatically via your ~/.bashrc by either:
###   a) Manually - by appending the following line into your ~/.bashrc:
###      - sudo /usr/local/bin/fix-etc-resolv.conf-wsl.sh
###   b) Using this shell command:
###      - echo "sudo /usr/local/bin/fix-etc-resolv.conf-wsl.sh" >> ~/.bashrc
###

resolvFile="/etc/resolv.conf"
linesToBeLastRegEx='^nameserver 8\.8\.(4\.4|8\.8)$'
backupFile="/tmp/resolv.conf.BAK.$(date +"%F_%H-%M-%S")"

cp "$resolvFile" "$backupFile"

cat \
	<(echo "# Processed by: $0 $@") \
	<(cat "$backupFile" | egrep -v "$linesToBeLastRegEx") \
	<(cat "$backupFile" | egrep "$linesToBeLastRegEx") \
\
	> "$resolvFile"