TCL set Special Characters in a string

Question

I want to set in TCL the below error message as a variable and compare with the error message from a network switch, by-passing the special characters

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Answer 1

If you use double quotes, you also have to escape "inner" quotes:

set x "Use \[slot/port] or \[\"portname\"] or \[slot/*] or \[*]."

Or use braces and avoid escaping altogether

set x {Use [slot/port] or ["portname"] or [slot/*] or [*].}

See Tcl's 12 syntax rules, numbers 4 and 6