On 31 Mar 2011, at 20:33, Roger Burton West wrote: > On Thu, Mar 31, 2011 at 08:22:26PM +0100, Shevek wrote: >> What am I doing wrong? > > You can't use shell functions (such as pipe) with the list-form > invocation of system(). Sorry, Shevek - I should have warned you about that beforehand.