Shell Programming and Scripting

the topic is about "echo" running locally

Right.

And what happens if you use the example:

ssh HostB "echo \`hostname\`"

You get a literal return of:

`hostname`

Not HostB

why don't you try it first and see for yourself. The escape char is used to prevent "hostname" from being evaluated from the current system instead passed to the target host

Why are you echoing.... JUST RUN THE COMMAND.

ssh HostB hostname

it will ssh and then execute the command, I dont understand why this is hard?

#10 - I did try it myself, that wasn't theory I replied w/ there, that was the actual results.

#11 - Of course I can just execute hostname and be done. Hostname is just a simple return command to test it w/.

The question is why can you not send echo remotely. It's used in many processes. What if I just wanted to check a remote environment variable across a span of hosts, you would think you could ssh a "echo $PATH" for example and see the remote path, but that would just print the local path.

Hostname itself isn't the goal, it's just a easy targeted command to identify if your results are actually remote or local.

Mass change a user's password? ssh HostA "echo user:tmppass|chpasswd", etc. Lots of uses for echo.

I've moved to making a script and pushing it remotely for the time being, and that's working, I'm just trying to gain an understanding here.

yes, i do understand your problem. if you want to pass the command to the target host machine you need to passed it like a regular string since you're using ssh.

the single qoute will probably do it for you or double qoutes plus escape char.

Code:

-bash-3.2$ ssh -l testid xav10-m 'echo $HOME'
/root/home/testid
-bash-3.2$ pwd
/home/erm/testid

some more testing

Code:

-bash-3.2$ ssh -l testid xav10-m 'echo \$HOME'
$HOME
-bash-3.2$ ssh -l testid xav10-m "echo \$HOME"
/root/home/testid
-bash-3.2$ echo $HOME
/home/erm/testid
-bash-3.2$ ssh -l testid xav10-m "echo $HOME"
/home/erm/testid
-bash-3.2$

the last testing says something like "hostA, process this and passed it to hostB" whereas the first testing would mean "passed this literal string and let hostB do the rest."

hope this helps you