(command.CommandList
  children: [
    (command.If
      arms: [
        (if_arm
          cond: 
            (condition.Shell
              commands: [
                (command.Sentence
                  child: 
                    (C {<Id.Lit_LBracket '['>} {($ Id.VSub_Pound '#')} {<-ne>} {<2>} 
                      {<Id.Lit_RBracket ']'>}
                    )
                  terminator: <Id.Op_Semi _>
                )
              ]
            )
          action: [
            (command.Simple
              words: [{<echo>} {(DQ <'Usage '> ($ Id.VSub_Number 0) <' from to'>)}]
              redirects: [(redir op:<Id.Redir_GreatAnd '>&'> loc:(redir_loc.Fd fd:1) arg:{<2>})]
              more_env: []
              do_fork: T
            )
            (command.Simple
              words: [{<echo>} {(DQ <'for e.g. '> ($ Id.VSub_Number 0) <' \'2 grams\' drams'>)}]
              redirects: [(redir op:<Id.Redir_GreatAnd '>&'> loc:(redir_loc.Fd fd:1) arg:{<2>})]
              more_env: []
              do_fork: T
            )
            (command.ControlFlow token:<Id.ControlFlow_Exit exit>)
          ]
          spids: [15 28]
        )
      ]
      else_action: []
      redirects: []
    )
    (C {<units>} {<-t>} {(DQ ($ Id.VSub_Number 1))} {(DQ ($ Id.VSub_Number 2))})
  ]
)