Generates a .htaccess file to block referer spam based on https://github.com/piwik/referrer-spam-blacklist.

generate-htaccess-referer-blacklist.sh

#!/bin/bash

# wget https://raw.githubusercontent.com/piwik/referrer-spam-blacklist/master/spammers.txt -O spammers.txt

{
    echo -ne 'RewriteEngine On\n\n' && \
    echo '# denied referers' && \
    cat spammers.txt | head -n -1 | sed 's/\./\\\./g' | sed 's/^\(.*\)$/RewriteCond "%{HTTP_REFERER}" "\1$" [NC,OR]/' && \
    cat spammers.txt | tail -n 1 | sed 's/\./\\\./g' | sed 's/^\(.*\)$/RewriteCond "%{HTTP_REFERER}" "\1$" [NC]/' && \
    echo 'RewriteRule .* - [F]'
} > referer.htaccess