Passing arguments to an interactive program non-interactively

I have a bash script that employs the read command to read arguments to commands interactively, for example yes/no options. Is there a way to call this script in a non-interactive script passing default option values as arguments?

It's not just one option that I have to pass to the interactive script.

Solution 1:

Many ways

pipe your input

echo "yes
no
maybe" | your_program

redirect from a file

your_program < answers.txt

use a here document (this can be very readable)

your_program << ANSWERS
yes
no
maybe
ANSWERS

use a here string

your_program <<< $'yes\nno\nmaybe\n'

Solution 2:

For more complex tasks there is expect ( http://en.wikipedia.org/wiki/Expect ). It basically simulates a user, you can code a script how to react to specific program outputs and related stuff.

This also works in cases like ssh that prohibits piping passwords to it.

Solution 3:

You can put the data in a file and re-direct it like this:

$ cat file.sh
#!/bin/bash

read x
read y
echo $x
echo $y

Data for the script:

$ cat data.txt
2
3

Executing the script:

$ file.sh < data.txt
2
3