title: cannot solve syntax error: operand expected (error token is "+")
body: <p>getting this error, where my code is:</p>
  
  <pre><code>#!/bin/bash
  
  # argument passed to script (or any other source if needed like intern to script)
  file=$1
  rs=$2
  clin_sig=$3
  mut_type=$4
  pos=$6
  allele=$7
  chain_pos=$8
  abs_pos=$(($pos+$chain_pos))
  echo $abs_pos
  </code></pre>
  
  <p>where command line is:</p>
  
  <pre><code>./program.sh 1 1 1 1 1 1 1
  ./program.sh: line 11: 1+: syntax error: operand expected (error token is "+")
  </code></pre>
  
  <p>similar questions have been solved using $(()) to do arithmetic, this is not working for me.</p>