ad_blocker_bash

adblock_hosts_modifier.sh

#!/bin/bash -e
# This will download files or set the hosts file to defaults.
# USAGE:
#    DESCRIPTION OF ENV VARS HERE
###############################################################################
set -e          # exit on command errors (so you MUST handle exit codes properly!)
set -o pipefail # capture fail exit codes in piped commands
#set -x         # execution tracing debug messages

# get switches
for i in "$@"
do
case $i in
	--enable|-e)
    ENABLED=true
    shift # past argument with no value
    ;;
    --disable|-d)
    DISABLED=true
    shift # past argument with no value
    ;;
    *)
            # unknown option
    ;;
esac
done

# allow hosts to be downloaded
if [ "$ENABLED" = true ]; then 
	# Hosts array this needs to be in text format. open any link for an example of hosts files online. that need to match that format
	declare -a arr=(
		"http://hosts-file.net/ad_servers.txt" 
		"http://pgl.yoyo.org/adservers/serverlist.php?hostformat=hosts&showintro=0&mimetype=plaintext" 
		"http://winhelp2002.mvps.org/hosts.txt" 
		"https://adaway.org/hosts.txt"
	) 

	# creating necessary files
	touch /tmp/test_merge_adblock.txt
	echo -e "# this file was generated at $(date) using the following host files:" > /tmp/hosts_complete

	# now loop through the above array
	for i in "${arr[@]}"
	do
		echo -e "downloading source host: $i"
		TEMP_TXT_NAME=$(printf "$i" | sha256sum | sed 's/\ //g' | sed 's/\-//g') # this creates a unique name for the file so it is almost impossible to run into conflicts.
		(curl "$i" > /tmp/"$TEMP_TXT_NAME"_adblock.txt)  >/dev/null 2>&1 # downloading the sources from above with unique name
		(sed -i 's/\r//' /tmp/"$TEMP_TXT_NAME"_adblock.txt) # converting proper line endings
		cat /tmp/"$TEMP_TXT_NAME"_adblock.txt >> /tmp/test_merge_adblock.txt # merging into a common file
		echo -e "# $i" >> /tmp/hosts_complete # adding source host url to completed host file for clerical purposes
	done

	echo -e "all hosts downloaded"

	# removing comments from the file using sed. This is due to many hosts files have many comments in them.
	(sed '/^#/ d' /tmp/test_merge_adblock.txt > /tmp/test_tmp_merge_adblock.txt) >/dev/null 2>&1
	mv -f /tmp/test_tmp_merge_adblock.txt /tmp/test_merge_adblock.txt

	# now we remove duplicate lines this includes empty lines
	awk '!seen[$0]++' /tmp/test_merge_adblock.txt >>  /tmp/hosts_complete

	# since the file is done, now we can move it to its proper place
	sudo mv /tmp/hosts_complete /etc/hosts

	# Setting the file to its original ownership in case this script was not run with sudo.
	sudo chown root:root /etc/hosts

	# clean up
	rm -rf /tmp/*_adblock.txt
	rm -rf /tmp/hosts_complete

	echo -e "all hosts merged"

elif [ "$DISABLED" = true ]; then # reset the file to stock.
	sudo rm -rf /etc/hosts
	echo -e "resetting hosts file to stock"
	echo -e "#
# /etc/hosts: static lookup table for host names
#

#<ip-address>	<hostname.domain.org>	<hostname>
127.0.0.1	localhost.localdomain	localhost
::1		localhost.localdomain	localhost

# End of file" > /tmp/hosts_complete
	sudo mv /tmp/hosts_complete /etc/hosts
	sudo chown root:root /etc/hosts
	rm -rf /tmp/hosts_complete
	echo -e "reset complete"
fi

# EOF