how to undo ctrl z debian code example

Example: how to take back crtl + z terminal

# just type fg and press enter
  fg [jobspec]
          Resume jobspec in the foreground, and make
          it  the  current  job.   If jobspec is not
          present, the shell’s notion of the current
          job  is used.  The return value is that of
          the command placed into the foreground, or
          failure  if  run  when job control is dis-
          abled  or,  when  run  with  job   control
          enabled,  if  jobspec  does  not specify a
          valid job or jobspec specifies a job  that
          was started without job control.