Note, for clarity (since it took me a bit of experimentation to make sure) that this only happens when the shell in which you attempt to run default_script.sh is dash; trying this in bash with /bin/sh -> dash isn't sufficient.
Note, for clarity (since it took me a bit of experimentation to make sure) that this only happens when the shell in which you attempt to run default_script.sh is dash; trying this in bash with /bin/sh -> dash isn't sufficient.