using only the second "<" would result in bash being called with a argument like "/dev/fd/N", which is where the output of the subshell is coming from. The fir

using only the second "<" would result in bash being called with a argument like "/dev/fd/N", which is where the output of the subshell is coming from. The first "<" redirects the output of this file descriptor into the stdin of bash. So both are needed, but you could just do it with a pipe :/