(CommandList
  children: [
    (C {(set)} {(-o)} {(errexit)})
    (C {(set)} {(-o)} {(nounset)})
    (C {(set)} {(-o)} {(pipefail)})
    (AndOr
      children: [
        (C {(grep)} {(SQ <"^hosts:.*myhostname">)} {(/etc/nsswitch.conf)})
        (Subshell
          child: 
            (C {(sed)} {(-e)} {(SQ <"s/^hosts:\\(.*\\)/hosts:\\1 myhostname/">)} {(-i)} 
              {(/etc/nsswitch.conf)}
            )
          spids: [79 94]
        )
      ]
      op_id: Op_DPipe
    )
  ]
)