Question

I run a linux command that sometimes asks for user input (press 1 or 2).

I always want to answer 1, how can I pass this value automatically ?

Answer 1

Use the pipe | operator to connect the output of one command to the input of another.

echo 1 | command

If you want to repeat some input to a command, you can use yes. By default it sends the string “y” repeatedly but it also repeat a different string of your choice.

yes | cp * /tmp  # Answer "y" to all of cp's "Are you sure?" prompts.
yes 1 | command  # Answer "1" repeatedly until the command exits.