(command.CommandList
  children: [
    (command.If
      arms: [
        (if_arm
          cond: [
            (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 '$0') <' from to'>)}]
              redirects: [(redir.Redir op:<Id.Redir_GreatAnd '>&'> fd:-1 arg_word:{<2>})]
            )
            (command.Simple
              words: [{<echo>} {(DQ <'for e.g. '> ($ Id.VSub_Number '$0') <" '2 grams' drams">)}]
              redirects: [(redir.Redir op:<Id.Redir_GreatAnd '>&'> fd:-1 arg_word:{<2>})]
            )
            (command.ControlFlow token:<Id.ControlFlow_Exit exit>)
          ]
          spids: [15 28]
        )
      ]
    )
    (C {<units>} {<-t>} {(DQ ($ Id.VSub_Number '$1'))} {(DQ ($ Id.VSub_Number '$2'))})
  ]
)