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How do I set up SSH so I don't have to type my password?

i execute the following command :- ssh -l admin hostname command but each time i execute it, it ask me to enter password ..... how i can give it password as default because i'm going to put in bash file ?

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migrated from stackoverflow.com Oct 3 '10 at 8:11

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marked as duplicate by Diago Oct 5 '10 at 7:17

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2 Answers

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The following information was obtained from here.

SSH login without password

Your aim:

You want to use Linux and OpenSSH to automize your tasks. Therefore you need an automatic login from host A / user a to Host B / user b. You don't want to enter any passwords, because you want to call ssh from a within a shell script. How to do it

First log in on A as user a and generate a pair of authentication keys. Do not enter a passphrase:

a@A:~> ssh-keygen -t rsa
Generating public/private rsa key pair.
Enter file in which to save the key (/home/a/.ssh/id_rsa): 
Created directory '/home/a/.ssh'.
Enter passphrase (empty for no passphrase): 
Enter same passphrase again: 
Your identification has been saved in /home/a/.ssh/id_rsa.
Your public key has been saved in /home/a/.ssh/id_rsa.pub.
The key fingerprint is:
3e:4f:05:79:3a:9f:96:7c:3b:ad:e9:58:37:bc:37:e4 a@A

Now use ssh to create a directory ~/.ssh as user b on B. (The directory may already exist, which is fine):

a@A:~> ssh b@B mkdir -p .ssh
b@B's password: 

Finally append a's new public key to b@B:.ssh/authorized_keys and enter b's password one last time:

a@A:~> cat .ssh/id_rsa.pub | ssh b@B 'cat >> .ssh/authorized_keys'
b@B's password: 

From now on you can log into B as b from A as a without password:

a@A:~> ssh b@B hostname
B

A note from one of our readers: Depending on your version of SSH you might also have to do the following changes:

  • Put the public key in .ssh/authorized_keys2
  • Change the permissions of .ssh to 700
  • Change the permissions of .ssh/authorized_keys2 to 640
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Use "sshpass" utility. This takes -p PASSWORD as an argument and pass it to ssh. 'sshpass -p MyPassword ssh -l admin hostname command' or safely from environment variable 'sshpass -e MYPASSWD ssh -l admin hostname command'

For more information, http://www.debianadmin.com/sshpass-non-interactive-ssh-password-authentication.html

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