Modify /etc/hosts file using a shell script

Question

I do not have passwordless ssh enabled between my two servers a and b. So I am using sshpass to connect to the server b from a.

I have a requirement to add host entries in the /etc/hosts of server b from a. But the user that i am logging into server b is non-root user but has sudo privileges to edit files owned by root.

How do i add host entries to /etc/hosts of server b from server a through a shell script while using sshpass.

Here is the script that was tried:

#!/bin/bash

export SSHPASS="password"
SSHUSER=ciuser
WPC_IP=10.8.150.28

sshpass -e ssh -o UserKnownHostsFile=/dev/null -o 'StrictHostKeyChecking no' $SSHUSER@$WPC_IP "echo test >> /etc/hosts"

Output:

bash test.sh
Warning: Permanently added '10.8.150.28' (RSA) to the list of known hosts.
bash: /etc/hosts: Permission denied

Thank you.

Can you post the command you tried and how it failed? – that other guy Dec 02 '16 at 21:05 — that other guy, Dec 02 '16 at 21:05
@thatotherguy: updated the question. Thanks – GSM Dec 02 '16 at 22:19 — GSM, Dec 02 '16 at 22:19

score 1 · Answer 1 · edited May 23 '17 at 12:16

sudo doesn't work with redirects directly, so you can use sudo tee -a to append to a file:

echo '1.2.3.4 test' | sudo tee -a /etc/hosts

In your command, this would be:

sshpass -e ssh -o UserKnownHostsFile=/dev/null -o 'StrictHostKeyChecking no' "$SSHUSER@$WPC_IP" "echo test | sudo tee -a /etc/hosts"

Note that this requires passwordless sudo access without a tty, which is not necessarily the same as your sudo privileges.

Modify /etc/hosts file using a shell script

1 Answers1