command fail with sed error on Mac OS X

[sebsto]

$ uname -a Darwin 15.6.0 Darwin Kernel Version 15.6.0: Thu Jun 23 18:25:34 PDT 2016; root:xnu-3248.60.10~1/RELEASE_X86_64 x86_64

$ cat ./lambda-shell

!/bin/bash

while : ; do read -p '$ ' cmd apex invoke exec <<<"{ "command": "$cmd" }" | sed 's/\n/\n/g; s/\t/\t/g; 1{ s/^"// }; ${ s/"$//; };' done

$ ./lambda-shell

$ ls sed: 1: "s/\n/\n/g; s/\t/\t/g; ...": bad flag in substitute command: '}'