(command.CommandList
  children: [
    (command.If
      arms: [
        (if_arm
          cond: 
            (condition.Shell
              commands: [
                (C {<Id.Lit_LBracket '['>} {($ Id.VSub_Pound '$#')} {<-ne>} {<1>} {<Id.Lit_RBracket ']'>})
              ]
            )
          action: [
            (C {<echo>} {(DQ <'Usage: '> ($ Id.VSub_Number '$0') <' <executable>'>)})
            (command.ControlFlow token:<Id.ControlFlow_Exit exit> arg_word:{<1>})
          ]
          spids: [4 16]
        )
      ]
    )
    (command.Pipeline
      children: [
        (C {<nm>} {<-d>} {<-n>} {($ Id.VSub_Number '$1')})
        (C {<grep>} {(SQ <' [bBdD] '>)})
        (C {<awk>} 
          {
            (SQ 
              <
'{  printf "%10ld kB  %s\\n", ($1-lastpos)/1024, lastname; lastpos=$1; lastname=$3 }'
              >
            )
          }
        )
        (C {<sort>} {<-n>})
      ]
      negated: F
    )
  ]
)