(command.CommandList
  children: [
    (command.Simple
      blame_tok: <set>
      more_env: []
      words: [{<set>} {<-o>} {<errexit>}]
      redirects: []
      do_fork: T
    )
    (command.Simple
      blame_tok: <set>
      more_env: []
      words: [{<set>} {<-o>} {<nounset>}]
      redirects: []
      do_fork: T
    )
    (command.Simple
      blame_tok: <set>
      more_env: []
      words: [{<set>} {<-o>} {<pipefail>}]
      redirects: []
      do_fork: T
    )
    (command.AndOr
      children: [
        (command.Simple
          blame_tok: <grep>
          more_env: []
          words: [{<grep>} {(SQ <'^hosts:.*myhostname'>)} {<'/etc/nsswitch.conf'>}]
          redirects: []
          do_fork: T
        )
        (command.Subshell
          left: <Id.Op_LParen _>
          child: 
            (command.Simple
              blame_tok: <sed>
              more_env: []
              words: [
                {<sed>}
                {<-e>}
                {(SQ <'s/^hosts:\\(.*\\)/hosts:\\1 myhostname/'>)}
                {<-i>}
                {<'/etc/nsswitch.conf'>}
              ]
              redirects: []
              do_fork: T
            )
          right: <Id.Right_Subshell _>
          redirects: []
        )
      ]
      ops: [<Id.Op_DPipe _>]
    )
  ]
)