On Thu, Dec 02, 2010 at 07:04:57PM +0800, Clark J. Wang wrote: > Following command also prints nothing, confused :( > > for ((i = 0; i < 10; ++i)); do echo -n " $i"; done | while read v; do echo > $v; done
The output from the first command in the pipeline does not end with a newline. Therefore, 'read' in the second command returns 'failure' (non-zero) when it reads the first line of input, and your loop never iterates.
