In some cases
gnome-terminal preferences doesn't have the select-by-word characters option. It still has the profile-ID you need for command-line configuration though: Obtain it in the edit -> profile preferences -> General tab on your profile.
dconf list /org/gnome/terminal/legacy/profiles:/:b1dcc9dd-5262-4d8d-a863-c897e6d979b9/
to check whether it works. If no output, then the profile-id is not b1dcc9dd-5262-4d8d-a863-c897e6d979b9, copy pate the one from the preferences as descibed above.
dconf write /org/gnome/terminal/legacy/profiles:/:b1dcc9dd-5262-4d8d-a863-c897e6d979b9/word-char-exceptions '@ms "-,.;?%&#_+@~·:$"'
with the correct profile-ID. Here I remove
= from the list but add
$ according to the OP's wish.
Note that you can still select a word which is split by this character, say
iceweasel/stable : double-click on the first part, then hold the
shift key and click on the second part.