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Expect and parameters with $

Posted by FullGaz (FullGaz), 3 April 2006

I am writing a script that logs on to different remote servers using ssh and then runs a program remotely.

On each server I have set an environment variable such as $MY_PROG_PATH so that I don't have to change my scripts if the program path changes.

I may use this script from the command line or call it from diverse Perl scripts using system().

Say the script is called run_remote.exp. It takes the server name as a parameter and then the command I want to run.

for instance, I might want to write:

run_remote.exp \$MY_PROG_PATH/ param1 param2

or run_remote.exp \$MY_PROG_PATH/ param1 param2

(Here the \ prevents the command line from interpreting the environment variable locally) .

The advantage of this approach is that each server knows what is the result of it's own $MY_PROG_PATH.

The problem is that the script sends the following command to the remote server:
{$MY_PROG_PATH/} param1 param2

which of course doesn't work because of the {}.

I've tried many combinations of backslashes, brackets and other signs, to no avail... Is there a solution?

I'm using very basic expect, using only expect and send with the -- option.

Thanks for your help.

Posted by admin (Graham Ellis), 3 April 2006
The extra curly braces are added in Tcl because the parameters are in a list; you can get rid of them by using join to turn them into a regular string.

Example - this sample code

puts $argv
puts [join $argv]

runs as follows

grahamellis$ tclsh tdo \$MINE/ 1 p2 {$MINE/} 1 p2 $MINE/ 1 p2

Posted by FullGaz (FullGaz), 3 April 2006
Graham, you're a genius!  
Thanks ever so much, I am so glad to have found this forum.
Of course this worked and solved all my problems  

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