Friday, February 11, 2011

Balyya interview with NDTV

Listen.... nobody plays with balayya.....
Pretty old new but worth watching.

Wednesday, February 9, 2011

SSH login without using password.


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:

Steps :-
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/
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/ | 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

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

Using expect script inside shell script

Written small sample shell script which contains expect script, which connect to ftp server.


echo "shell script starting"
sleep 2
sleep 2
echo "expect is starting"
expect -c "
spawn ftp
expect ":"
send \"user_name\r\"
sleep 1
expect "Password:"
send \"user_passed\r\"
sleep 1
expect "ftp\*"
send \"bye\r\"
sleep 1
expect eof"
echo "expect ended bash script follows"
ls -l
sleep 1
sleep 2