Enable Perl-CGI at Apache2

Enable CGI:
#ln -s /etc/apache2/conf-available/serve-cgi-bin.conf /etc/apache2/conf-enabled/serve-cgi-bin.conf
#ln -s /etc/apache2/mods-available/cgi.load /etc/apache2/mods-enabled/cgi.load

Add a CGI script:
#touch /usr/lib/cgi-bin/test.pl
#vi /usr/lib/cgi-bin/test.pl
-----------------------------
#!/usr/bin/perl
print "Content-type: text/html\n\n";
print "Testing";
:wq!
-----------------------------
#cd /usr/lib
#chmod -R +x ./cgi-bin

Restart Apache2:
#systemctl restart apache2.service

Verify:
Access http://127.0.0.1/cgi-bin/test.pl