#!/bin/bash

HOSTFILE=/etc/hosts

BLOCKFILE=~/.hostblock

UNBLOCK=false

WHO=`whoami`

DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

VERBOSE=true

function OUTPUT()

{

if $VERBOSE ; then

echo $@

fi

}

function USAGE()

{

echo "Bad usage."

}

function READ_OPTS()

{

# read flags

while getopts ":u" OPTION; do

case $OPTION in

u)

UNBLOCK=true

;;

?)

USAGE

exit 1

;;

esac

done

shift $((OPTIND - 1))

# read args

BLOCKSITES=$1

}

function BLOCKSITE()

{

site=$1

if $UNBLOCK ; then

OUTPUT "un blocking $1"

# remove if exists

sed -i -r "s/(^127\.0\.0\.1 $site www.$site hostblock$)/#HOSTUNBLOCK: \1/g" $HOSTFILE

else

OUTPUT "blocking $1"

# this could be written better...

# check if already blocked

grep -qE "^127\.0\.0\.1 $site www.$site hostblock$" $HOSTFILE

if [ $? = 0 ]; then

OUTPUT ' `- already blocked'

else

# check if unblocked

grep -qE "^#HOSTUNBLOCK: 127\.0\.0\.1 $site www.$site hostblock$" $HOSTFILE

if [ $? = 0 ]; then

# yes was blocked, unblock

sed -i -r "s/^#HOSTUNBLOCK: (127\.0\.0\.1 $site www.$site hostblock$)/\1/g" $HOSTFILE

else

# not blocked before, add it

echo "127.0.0.1 $site www.$site hostblock" >> $HOSTFILE

fi

fi

fi

}

#

# Start script.

#

# Run as root.

if [ "$WHO" != "root" ]; then

OUTPUT "Running as root"

sudo $DIR/hostblock $@

exit $?

fi

# Read cmd opts.

READ_OPTS $@

# Check for block sites.

if [ -z "$BLOCKSITES" ]; then

if [ ! -f $BLOCKFILE ]; then

echo "$BLOCKFILE does not exist"

exit 1

fi

BLOCKSITES=`cat $BLOCKFILE`

fi

# Block each site.

for site in $BLOCKSITES; do

BLOCKSITE $site

done