bash passing String to command, awaiting user input

I am trying to pass a string to command which waits for input to be entered on command line, I need to automate the user input process, luckily the string is static it wont change, I can hardcode it. Things I have tried so far

1. echo "hardcoded string" | /tmp/command
2. /tmp/command < hardcoded.txt

It still it asks input, i cannot use expect or autoexpect.

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