login to multiple server

Shell Programming and Scripting
1

i want to login (telnet) to 2 different servers. Then I will execute command in those servers as many time as I need(i will choose the server to execute the command). Is it possible?

i.e, my script will be stayed log on two servers (server1, server2). Then I will execute command by choosing one server at a time. It will take input from the terminal and decide from which the command has to be executed. I wanna to avoid login every time I need to execute command.

it may be bash, perl or others. i can log on using expect script. please help me

2

I would suggest using passwordless SSH instead of telnet(1), you can then run:

# ssh user@server.domain.com command

Do you can do something like:

COMMAND="ls -l"
SERVERNAME=server.domain.com
ssh user@${SERVERNAME} "${COMMAND}"

And use a case statement to select the server depending on what command you have selected if the command is to be a parameter to your script then that line needs to be:

COMMAND="$@"
if [ -z "${COMMAND}" ]; then
  echo "ERROR: No command given as parameter, aborting!"
  exit 99
fi

.

Either that or look into using /etc/hosts.equiv on the server but telnet and hosts.equiv are insecure.

Does this help?

3

Thanks TonyFullerMalv for ur quick reply!

passwordless SSH is not possible for me as I'm not root user of the server. Is it possible by using subshell?

4

you can be any user to use passwordless ssh .So you can proceed with TonyFullerMalv's suggestion.

5

Thanks TonyFullerMalv
I can use either ssh or telnet. It is not the problem. I do not want to log on every time I execute the command. Main thing is that I will be stayed log on to two servers from a single script and It will execute my desired command to desired server taking input of the shell.
Is it possible by using subshell? i'm not clear about subshell.