add/remove ssh keys using shell script

[sskraju]

Hi All

I'm new to linux.I need to add one ssh key & remove another key in 20 RHEL remote servers.

key to delete:
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEAqgYqpC+019HDOc5MJ1MqTm 01iubY0nQqbbbjODRWgUlyH+uLUM+NLHpPaWKlVPNpGLmg0uK+ bOXXUprLGxAAHQKgF141lgBPCjW3VfFwTDtK3d1yEOcbMULCBB Bvui2NViUJCkExK7CRO== user1

key to add:
ssh-rsa AAAAB3NzaC1yc2EAAAABIwAAAQEA0TGyZUJD43KsHWZhJJuPr3 UB5ubTVT1wE+ffQYJkIiE2539u8v5SVpWHWq6QEB/nDS0CEQPZzO91iqw652Pm+eLTlLf+JJ/jb5uqMdN0ErJcrBn0ILUfjbMRHKj2pry/mV87QhL4bhJRc== user2

My idea is to add key that has to be add/remove in text file (key.txt) and server ip's (ip.txt).Then call these files using script.

To add key : nothing has to be compared as i'm sure this is new key.the new key shud be appended in .ssh/authorized_keys

to remove key: we have to compare all the existing keys in remote server with the present key which we are removing...remove that key & save .ssh/authorized_keys

Can any one provide two scripts (to add & remove) for this requirement.I hope that is good to copy already existing keys to tmp..then do the changes.. I have little knowledge in programming so providing complete script will be very much helpful

Let me know if any other easy method is possible..Plz share your opinions

Thanks in Advance
SSK Raju

[druidmatrix]

You can try and write a Perl script that will do this easily for you if you have do it on 100's of servers. Hint: Net::SSH::Perl

But just for 20 servers, I'd suggest just log in and do it manually:
vi the $HOME/.ssh/authorized_keys(2) file and delete the line with the key you need to remove, and copy/paste the new one (be careful of extraneous newline characters).

[kai12]

hi SSK Raju,

are you familiar with the ssh-add tool? it seems to do exactly what you are asking for (or else, I didn't get what you are trying to do, in which case, maybe you can clarify).

I particular, ssh-add supports a "-d" flag for removing keys.

Of course, this still leaves the problem of logging into your 20 servers and executing those ssh-add commands.

cheers, kai