Passing inputs to multiple commands in bash script

Question

I want to auto set the user password. For example I want to set the password for a no-root user to a value stored somewhere else in the script.

I am doing the following:

echo $input | passwd $user

However it fails since there is a prompt for Retype the new password.

I tried:

echo $input | passwd $user
echo $input | Retype New Password:

with no luck. It says password change aborted. How do I accomplish this? Does calling out for retyping a new password invokes another shell process?

Ben Grimm · Accepted Answer · 2017-08-17 04:06:09Z

4

Just insert a newline:

echo $input$'\n'$input | passwd $user

Or use echo -e

echo -e "$input\n$input" | passwd $user

answered Feb 4, 2015 at 19:11

Ben Grimm

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4 Comments

Thanks @Ben Grimm. Worked like a charm. Can you please explain why new line works?

echoing text to STDIN of a process is effectively the same as typing, and the enter key produces a \n.

@brotherofmysister You should accept the answer if it worked for you.

sorry was offline for an hour :) Thanks @ Ben Grimm