there are two steps to start OVS on ovs"s official website, as follows:

$ export PATH=$PATH:/usr/local/share/openvswitch/scripts
$ ovs-ctl start

there is no problem with executing these two sentences separately in the terminal, but when I want to put them in a .sh file as a startup script, the shell script cannot be executed. The
script contains these two lines of code, and the error is that the command ovs-ctl cannot be found. In other words, the sentence export does not work.
what is the reason for this?