text: read_celllib osu018_stdcells.lib
  read_verilog unit.v
  read_sdc unit.sdc
  read_spef unit.spef
  
  # show the lineage
  dump_lineage
  
  # show the timer details
  dump_timer
  report_tns
  
  # change time and capacitance scales
  set_units -time 1ps -capacitance 1fF
  report_tns
  
  # restore time and capacitance scales
  set_units -time 1ns -capacitance 1pF
  report_tns
  
  # rescale time and capacitance scales
  set_units -time 2ns -capacitance 2pF
  report_tns
  