If a run the script more like is 8.3.1, I have the message: /bin/more:line 37:let - : syntax error: operand expected (error token is "-". The line 37 is: let LINE-COUNTER=$LINE_COUNTER - 1 Now, I do not have error because the line above in my script is: let LINE-COUNTER=$LINE_COUNTER 1 There is no more the "-"