Flush mod_pagespeed cache in Debian

view story

http://serverfault.com – I need a way to flush the mod_pagespeed cache while developing. According to mod_pagespeed documents, I should run the following command: sudo touch /var/mod_pagespeed/cache/cache.flush In Debian it's "su" instead of "sudo". However, it doesn't work for me; there's no "touch" command, nor is there any "cache.flush" file in the defined directory. Have I missed something? You kick-ass Linux users, please be humble - I'm pretty new to these stuff. Thank you in advance! (HowTos)