Assuming that you're meant to type this in a shell, this is a command substitution. The shell executes the command
DynamsoftBarcodeReader and replaces
$(DynamsoftBarcodeReader) in that command line by the output obtained by running
DynamsoftBarcodeReader. For example, if the command
/home/pi/Desktop/dbr, then the target of the symlink will be
Note to future visitors: in a makefile, the syntax
$(…) has a different meaning: it takes the value of a variable. This tutorial doesn't mention makefiles anywhere, so presumably the command is intended to be typed on the command line, in a shell such as bash, and there it's a command substitution.
$ was actually in a symbolic link, it would have no special meaning, the symlink would just be pointing to a target that happens to contain the character
$. But that's not happening here.