create variable with calculated number of spaces.

[Ray Andrews <rayandrews@xxxxxxxxxxx>]

    So I want to adjust the length of string1.
      I do this  by inserting a spacer in string1 who's length is
      calculated from the length of string2:
      
          local diff spacer
          (( diff = $#string2 - 76 ))
          for (( dd=1; dd<diff; dd++ )); do spacer+=' '; done
          ... # spacer will be incorporated into string1, not shown.
      
      It works fine, but I'll bet there's a less laborious way -- some
      way of creating 'spacer' with  'diff' number of spaces without the
      for loop.  I could make 'spacer' too long and then cut it at an
      index [diff], but I doubt that's as simple as it could be.  I know
      it's there, I just can't quite remember.