How to disable all caching and aggregation?

?How to disable all caching, css and js aggregation for theme development and how to display PHP errors on screen for debugging, including WSOD issues?

!When working in the development mode with any site hosted on your Aegir instance, you’ll want to work with our optimized caching systems turned off. There is a very easy to use auto-switch available for dev/prod environments. Any site you create (or access) with “dev.” anywhere in the subdomain alias, will have some caching systems disabled on the fly, automatically, while some other caching settings will be available to turn them off/on manually, because they will be no longer hardcoded. It is an important difference, because some people believe that the magic “dev.” switch in the subdomain will simply force all caches to be disabled, which is not the case. What is disabled automatically then? Only Speed Booster system and Cache integration will be disabled, while all settings on the standard admin/settings/performance page in D6 and admin/config/development/performance in D7 will be no longer hardcoded, so you can turn them on/off as you wish – but remember – it will be turned on/off only when you access the site with the “dev.” type subdomain, while any visits to non-dev URLs will still experience hardcoded caching. Also, the “dev.” in the subdomain will automatically enable, also on the fly, all PHP errors, for easier debugging of issues, including those causing otherwise complete WSOD. Note that you don’t need to rename the site to be able to work on it in the “dev-mode”. Simply add an extra domain alias with “dev.” (anywhere) and use it to access the site, when you wish to skip all otherwise hardcoded caching settings. Note also that “Page Compression” is always forced as disabled, even for “dev.” subdomains to avoid double compression, because everything is compressed on the fly on the Nginx level.