This command (in TclX) compares two strings for equality. It returns 1 if string1 and string2 are the identical and 0 if they are not. This command is a short-cut for string compare and avoids the problems with string expressions being treated unintentionally as numbers.
This command is UTF-aware and will also work on binary data.
Now (since Tcl 8.1.1) in the core as string equal.