At the end of trip.es, it attempts to check heredocs by calling to es, however, this doesn't do what is expected if the newly built es is first in the path (or in my case, in the path at all). errorcheck 'incomplete heredoc' {es -c 'cat<<eof'} 'pending' should be changed to something like errorcheck 'incomplete heredoc' {$es -c 'cat<<eof'} 'pending'