How to automate SSH login with password? ssh autologin

How to automate SSH login with password?

Before we begin, I would like to highlight that you are recommended to use public key authentication method if you want to setup login via ssh to any machines without the use of password instead of the method describe next. This is because it is more secure. There are plenty of articles in the web that explain why and please search for it if you want to know more.

Since I mentioned public key authentication is more preferred, why are we still interested in the method that we are going to explore next? Well in some machines or environments, public key authentication was not setup and you might not have the privelleges to set it up. If you happened to be in the senario decribed above and are in a hurry to ssh to a large number of machines to perform some tasks, below method might come in handy for you.

Step 1
Create a custom script using expect scripting language. As an example name the script as auto_login. The first line of the script should look like below.

Step 2
Setup three variables that will store user input for ssh login process. Basically these are hostname, userid and password.
set hostname [lindex $argv 0]
set pwd [lindex $argv 1]
set userid [lindex $argv2]

Step 3
Provide the syntax that will initiate the ssh process using the variables defined in step 2.
spawn ssh "$userid\@$hostname"

Step 4
Provide the syntax on what condition the script to start inputing the password. Usually it will be at the prompt for password. Notice the letter "P" is omitted below. This is due to some prompt wil use "P" and some "p".
expect "assword:*"

Step 5
Provide the syntax to input the password and give you the session for your task after login.
send "$pwd\r"

Basically the whole script will look like below.
set hostname [lindex $argv 0]
set pwd [lindex $argv 1]
set userid [lindex $argv2]
spawn ssh "$userid\@$hostname"
expect "assword:*"
send "$pwd\r"

Now you can try to test it out.
./auto_login "hostname" "password" "userid"
0 (0)
Article Rating (No Votes)
Rate this article
There are no attachments for this article.
There are no comments for this article. Be the first to post a comment.
Full Name
Email Address
Security Code Security Code
Related Articles RSS Feed
LVM: Reduce root PV/VG
Viewed 964 times since Sat, Jun 2, 2018
Manage Linux Password Expiration and Aging Using chage
Viewed 1522 times since Tue, Sep 11, 2018
stunnel Howto A Guide to create SSL access to a HTTP-only webserver with stunnel
Viewed 564 times since Fri, Sep 28, 2018 gives you books for free to study Linux
Viewed 944 times since Sat, Jun 2, 2018
OCFS2 Cluster File System Setup Guide in Linux
Viewed 1754 times since Sat, Jun 2, 2018
debian Debian/Ubuntu Linux: Find If Installed APT Package Includes a Fix/Patch Via CVE Number
Viewed 564 times since Sun, Sep 23, 2018
Linux RAID Mdadm Cheat Sheet
Viewed 563 times since Fri, May 15, 2020
RHEL: Extending the maximum inode count on a ext2/ext3/ext4 filesystem
Viewed 1193 times since Sun, May 27, 2018
Linux – Securing your important files with XFS extendend attributes
Viewed 587 times since Wed, Jul 25, 2018
RHEL: Remove existing SAN LUNs
Viewed 1056 times since Sat, Jun 2, 2018