When dealing with numbers in bash when is [[ ]] preferred over (( )) -

There is a reason to just love something out of curiosity:

  while [[ $ Number -lt 10]]   
 more  
  while (($ number <10))   
 They seem to be doing the same thing; I am thinking that maybe one of them has the benefit of a performance or maybe some portability concerns be with  [[]] ?   
 
 
 Neither standard, therefore portability is not an issue. If you are simply doing simple comparisons, there is no difference between it  
  if [[$ number -lt 10]]   
 and  < $  from the other with the ability to drop from one side (because all the stars are assumed) before>  if ((number> <10))  < / Pre> 
 may be variables and derivatives) and readability.  
 You can like  [[... ...]  when adding mathematical and non-arithmetic tests to your code:  
  If the [[$ $ number -010 & amp; $ File = * .txt]]   
 versus  
  if ((number & lt; 10)) & amp; Amp; [[$ File = * .txt]]   
 You probably want  ((...))  if you have some computations in comparison to you:  
  if ((number * 2 <10-delta))   
 unnecessary complicated vs  
  if [[$ ( (Number * 2)) -Lattie $ ((10-delta)]]