return value from subshell and output to local variables

From the bash manual, Shell Builtin Commands section:

local:
    [...]The return status is zero unless local is used outside a function, an invalid name is supplied, or name is a readonly variable. 

Hope this helps =)

To capture subshell's exit status, declare the variable as local before the assignment, for example, the following script

#!/bin/sh

local_test()
{
    local local_var
    local_var=$(echo "hello from subshell"; exit 1)
    echo "subshell exited with $?"
    echo "local_var=$local_var"
}

echo "before invocation local_var=$local_var in global scope"
local_test
echo "after invocation local_var=$local_var in global scope"

produces the following output

before invocation local_var= in global scope
subshell exited with 1
local_var=hello from subshell
after invocation local_var= in global scope