[EOSIO/eos] eosiocpp: command not found (#5333)

GuangdeMacBook-Pro:hello tg$ ls
CMakeLists.txt hello.abi hello.cpp hello.hi_rc.md hello_rc.md
GuangdeMacBook-Pro:hello tg$ eosiocpp -o hello.api hello.cpp
-bash: eosiocpp: command not found