Added shell builtin command.
Added shell builtin command.

pashinin/fabric,bspink/fabric,mathiasertl/fabric,kmonsoor/fabric,sdelements/fabric,bitmonk/fabric,SamuelMarks/fabric,jaraco/fabric,cgvarela/fabric,hrubi/fabric,cmattoon/fabric,simon-engledew/fabric,MjAbuz/fabric,itoed/fabric,likesxuqiang/fabric,askulkarni2/fabric,opavader/fabric,tekapo/fabric,tolbkni/fabric,ploxiln/fabric,amaniak/fabric,akaariai/fabric,TarasRudnyk/fabric,StackStorm/fabric,fernandezcuesta/fabric,rane-hs/fabric-py3,raimon49/fabric,haridsv/fabric,felix-d/fabric,elijah513/fabric,rbramwell/fabric,kxxoling/fabric,ericholscher/fabric,qinrong/fabric,bitprophet/fabric,pgroudas/fabric,rodrigc/fabric,xLegoz/fabric,getsentry/fabric