Is it possible to use a variable from bash in expect?

Question

linux

I'll outline the gist.
On a remote machine, I need to get the user's UID. Then you need to perform actions on the same remote machine using this UID. Those. it must be obtained and somehow stored in a variable that would then be used.
query like this

send "cat /etc/passwd | grep myuser | awk -F ":" '{print $3}'\r"

did not pass because it is necessary to escape this "$3" apparently. And the backslash didn't fit
send "cat /etc/passwd | grep myuser >info.txt\r"
. On my machine I can get the UID but still a problem. It must also be inserted into the send "here =)" command, tell me how to insert a variable. (I will also be glad if you tell me with escaping so that the file is not copied in vain)
....
As I understand it, you need to somehow work with tcl variables? But I will get the number from bash...
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ANSWER: in bash we do export var=12345
then in the tcl environment itself (inside the expect entry):
send "$env(var)\r" (where env - Used for representing the array of elements that are environmental variables.)
tcl syntax
www.tutorialspoint.com/tcl-tk/tcl_special_variables.htm
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Answer 1

On a remote machine, I need to get the user's UID. Then you need to perform actions on the same remote machine using this UID. Those. it must be obtained and somehow stored in a variable that would then be used.

If I understand the essence of the question correctly, then you can write the result into a variable like this:

myvar=`cat /etc/passwd | grep myuser | awk -F ":" '{print $3}'\r`