0 400   0   hello="hello, "
 0 400   0   hello+=word
 0 400   0   echo $hello
 1 400   0   
 2 400   0 + for ((i = 2; i > 0; i--)); do
 0 401   0 |    echo postfix dec $i
 0 401   0 | done
 2 400   0 + for ((i = 2; i > 0; --i)); do
 0 401   0 |    echo prefix dec $i
 0 401   0 | done
 2 400   0 + for ((i = 0; i < 2; i++)); do
 0 401   0 |    echo postfix inc $i
 0 401   0 | done
 2 400   0 + for ((i = 0; i < 2; ++i)); do
 0 401   0 |    echo prefix inc $i
 0 401   0 | done
 1 400   0   
 0 400   0   # issue 215
 2 400   0 + for ((i = 0; i < 2; i++)); do
 0 401   0 |   echo $((((1)) << i))
 0 401   0 | done
 0 400   0