pxe rc.local linux Stretch script not executed

I need to run a script via a linux stretch pxe. The script that is run in the rc.local that runs an ex.sh script does not run directly. I have the following message

"expected unary operator"

. It is a test (if entry = yes ...) following a read.The command

journalctl

shows that the rc.local is well executed and the script .sh too. In fact the script passes the entry to the keyboard and gives the login! Of course I tried:

- put == instead of =,
- put the rc.local via systemclt and systemd ...

• ... In Debian 6 and 7 it's ok not in 9! An idea ?