Provide way to source Bash helper methods to remote hosts

[nickjer]

The Bash helper methods:

• create_passwd
• find_port
• ...

may need to be used on the host machines assigned to the batch job aside from the master node. One example is to start servers on the worker nodes using pbsdsh .... In order to start the servers we need to choose an available port to listen on using the find_port helper function.

One simple way to make the Bash helper methods more portable is to wrap them up in another Bash function such as...

source_helpers () {
  find_port () {
    # ...
  }
  create_passwd () {
    # ...
  }
  # ...
}
export -f source_helpers

by calling source_helpers in the main script, all of those functions are now available to it.

To make it available to pbsdsh scripts we could do...

pbsdsh bash -c "
  $(declare -f source_helpers)
  source_helpers

  ./start_server --port \$(find_port)
" &

The declare statement basically dumps the code for the helper functions in-place. Then we call that function to make the helpers available.