Get block size bash

Probe for block size. Useful when you've probably got no tools. Like when trying to optimize sqlite paging at run-time.

function block_size() {( 
   [ "$1" ] && cd $1; echo 1 > block_size.tmp;  
   ls --block-size 1 -s block_size.tmp | cut -f 1 -d ' '; 
   rm block_size.tmp; 
)}