Pass input to interactive command line program in bash

Question

I have a program that has its own prompt

example_program>

I need to run a series of command via this program

example_program> command_A
example_program> command B
Please enter input: [input_here]
example_program> command C

I can send commands A,B,C via the following line in a shell script:

(echo "command_C" && cat) | (echo "command_B" && cat) | (echo "command_A" && cat ) | example_program

How can I enter in the input needed and am prompted for after command B ([input_here])?

I do not have access to send or expect.

Answer 1

I'm guessing this will work, but it's only a guess since we don't know how your program is reading the responses: use a here-doc, and put the input for command B after invoking command B

example_program <<'END'
command_A
command B
input_here
command C
END