Ssh - running commands on remote server

Shell Programming and Scripting
1

Hi,

I am trying to run commands on a list of servers that I can ssh to and just want to know if there is a 'cleaner' way of doing this.

At the moment, I am doing as below. Is there a way that I can escape the double quote differently? If a use a single quote to enclose the commands that I want to run, it does not evaluate the variable even though they are enclosed in curly braces.

FYI, I am using Korn shell. Thanks in advance.

test_ssh ()
{
for server in ${server_list}
do
   echo
   echo "/+ ---------------------------------------------------------------------------------------------- +/"
   echo
   echo "- ssh test on server => ${server} - FIRST cat"
   testfile="/tmp/${server}_tmp"
   echo ""
   ssh ${server} "cat ${testfile}"
   echo ""
   ssh ${server} "touch ${testfile}"
   ssh ${server} "ls -l ${testfile}"

   marker="${marker_start} - `date`"
   #echo "- marker = ${marker}"
   ssh ${server} "echo \"\" >> ${testfile}"
   ssh ${server} "echo \"${marker}\" >> ${testfile}"
   ssh ${server} "echo \"\" >> ${testfile}"
   echo ""
   echo "- ssh test on server => ${server} - SECOND cat"
   ssh ${server} "cat ${testfile}"
   echo ""
   sleep 5
   echo
   echo "/+ ---------------------------------------------------------------------------------------------- +/"
   echo
done
}
2

Certainly you shouldn't run ssh for every single command, as this needs a login and process creation on the remote server. Collect your commands into a script and run that from a single login.
And - you should be very clear about where those "testfile"s are located.