How to send input to a program using sh script

Question

I wrote a script that I thought would send input to the terminal when the program request input. I use echo for this.

password=open1234
for I in "a" "b" "c" "d" "e" "f" "g"
do
    passwd ${I}
    echo ${password}
done

This is basically the form of the program. As you can see, i'm trying to change the passwords of multiple users using a script. The problem is that the input from echo never gets sent to the passwd program.

Community · Accepted Answer · 2017-05-23 12:28:43Z

2

As written here, you must add --stdin option to passwd.

echo "${password}" | passwd "${I}" --stdin

edited May 23, 2017 at 12:28

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answered Feb 19, 2014 at 6:13

loentar

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3 Comments

jax Over a year ago

Thanks, why doesn't echo work? Does it send to stdout insead of stdin?

loentar Over a year ago

Echo does work and it prints text to stdout. To connect passwd's stdin and echo's stdout you should pipe it using |.

jax Over a year ago

I tried it, but it doesn't work. All it does is echo the password onto the terminal, but not to the input stream.

MLSC · Accepted Answer · 2014-02-19 06:42:27Z

1

simply use(It would change all users to the same password):

#!/bin/bash
script='
passwd $user <<PASS
open1234
open1234
PASS
'
for user in $(cat user.txt)
do
   $script
done

answered Feb 19, 2014 at 6:42

MLSC

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1 Comment

jax Over a year ago

Thanks. I looked at the reference and found out why it is used.

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