I'm trying to find a regex that works to match a string of escape characters (an Expect response, see [this question](https://stackoverflow.com/questions/1988811/expect-get-variable-from-screen-region-based-on-row-and-column)) and a six digit number (with alpha-numeric first character).

Here's the whole string I need to identify: 

```
\r\n\u001b[1;14HX76196

```

Ultimately I need to extract the string:

```
X76196 

```

Here's what I have already:

```
interact {
        #...
        #...
        #this expression does not identify the screen location
        #I need to find "\r\n\u001b[1;14H" AND "([a-zA-Z0-9]{1})[0-9]{5}$"
        #This regex was what I was using before.
        -nobuffer -re {^([a-zA-Z0-9]{1})?[0-9]{5}$} {
                set number $interact_out(0,string)
        }   

```

I need to identify the escape characters to to verify that it is a field in that screen region. So I need a regex that includes that first portion, but the backslashes are confusing me...

Also once I have the full string in the $number variable, how do I isolate just the number in another variable in Tcl?