Shell Programming and Scripting

Hello to all

Background info:
Local machine : Linux, /bin/bash
Remote machine (for the user used for ssh) : SunOs, /bin/ksh
(so we have different OS, different Shells)

My problem :
From the local host i execute

Code:

$   var=bla
$   result=$(ssh -q user@remote-machine "
> echo \"this is var: $var \"
> var2=ggg
> echo \"this is var2 : $var2 \"
> "
> ) 
$   echo "$result"                   
this is var: bla 
this is var2 :

So, as you can see I want to open a ssh session on a remote machine and a want to shift a variable there also (in my case variable $var ). From what I know I can only do that by using the syntax : ssh user@machine " command " , so I used double quotes to describe the commands which I wanna execute via ssh. So, from my example you can see that I can shift the $var variable on the remote session, but I cannot create and/or call (?) another variable $var2 .
If I use ' ' (simple quotes) instead of " " . I can create the variable $var2 , but I cannot shift the variable $var :| .

I tried the same thing when the remote machine was Linux with /bin/sh shell for the user used for ssh. The results are the same, so I don't think it is an issue of different OS or different shells

Any ideas?

P.S. : i dont want to use workarounds such as declare $var in a file, scp the file on the remote host and source it there.

P.P.S. I cannot use rsh, remotexec.

Try this...

Code:

$   var=bla
$   result=$(ssh -q user@remote-machine "
> echo \"this is var: $var \"
> var2=ggg
> echo \"this is var2 : \$var2 \"
> "
> )

Reason:- Since you are setting var2 inside the ssh command, $var2 will be available only within that ssh scope
--ahamed

To explain why that's needed, type this into your shell:

Code:

$ echo "LINE=stuff;  echo $LINE"
LINE=stuff;  echo
$

...which of course doesn't execute 'echo $LINE'. But you see the problem: ssh doesn'g even get 'echo $LINE', it gets 'echo', because the shell helpfully substitutes $LINE for you before it's even fed to the command -- in this case echo, in your case ssh...

Either single-quote it, or escape it.

Code:

$ echo 'LINE=stuff; echo $LINE'
LINE=stuff; echo $LINE

$ echo "LINE=stuff; echo \$LINE"
LINE=stuff; echo $LINE

$

Thank you very much, indeed that was the answer to my problem

I have a new problem related with the one above (we still have same background info from the 1st post) :

Code:

h3mis391_telnet=h3mis391bin
ssh -q user@station " i=h3mis391
> eval value=\$`echo \${i}_telnet`
> echo value is $value
> "
value is

So the variable $value is not set.
I've also tried the remote eval command this way:

Code:

eval value=$`echo ${i}_telnet`
eval value=$`echo \${i}_telnet`

With the same result.
So I basically want to create (while I'm in a remote ssh session) the variable value. $value should take the content of the variable h3mis391_telnet (which was set in the initial session, before ssh).But I need to call the variable h3mis391_telnet using variable $i (set after ssh). I wanna use the value of $i variable to create the name of the $h3mis391_telnet, and this name I wanna use in order to call the variable in the eval command.
The idea it;s a bit complicated but the code shouldn;t be hard to understand.

Any help regarding the suntax I use or different approach to accomplish what I want?

---------- Post updated at 05:38 AM ---------- Previous update was at 05:25 AM ----------

To be more clear, this is what I want but done in only one session , without ssh :

Code:

h3mis391_telnet=h3mis391bin
i=h3mis391
eval value=$`echo ${i}_telnet`
echo "value is $value "
value is h3mis391bin

So this way it works. The only difference is that I want

Code:

h3mis391_telnet=h3mis391bin

------------------------------------> to use ssh in this point

Code:

i=h3mis391
eval value=$`echo ${i}_telnet`
echo "value is $value "
value is h3mis391bin

Moderator's Comments:

How to use code tags

---------- Post updated at 07:54 AM ---------- Previous update was at 05:38 AM ----------

Yes, I've made a mistake. It works like this :

Code:

h3mis391_telnet=h3mis391bin
ssh -q user@server " i=h3mis391
> eval value=$`echo \${i}_telnet`
>  echo value is $value
> "
value is h3mis391bin

The difference was here :

Code:

eval value=$`echo \${i}_telnet`   # good
eval value=\$`echo \${i}_telnet`  # bad

But I'm not 100 % sure why... o.O

You do know telnet is a reserved word (since its a command...) don't you?
It is maybe time to get to good practice: Use UPPERCASE for Variables! then it will not be misunderstood...

(Depending on what display I am I do not see underscores...)

Do a search, there has been a similar post not long ago... ( with PWD...)