Are you using a text editor that can't index your repo and do search-replace within? Vim and emacs both do this easily.
If you're not using an IDE, have you considered that by DRY-ing up constants, you're adding about 2-3 steps to even see what the value of a constant is?
Jump to the top of your file, figure out where the import is from, open the other file, then find constant name.
You also force your code reviewers to do this in e.g. GitHub, where there's no convenient 'jump to definition'.
IMHO, if your starting point is that you won't use sed, can't use a good IDE, and won't configure your editor nicely, then you're just creating a lot of unnecessary work for yourself, regardless of whether you're doing DRY.
Power tools are appropriate if you're building a house.
You're just going to wind up making changes where you don't need them that way. There's no guarantee that because the code looks the same it does the same. An IDE can't figure out what side-effects will happen.
By just letting your IDE make changes globally, you're running the risk of introducing bugs. By DRYng up your code, you know that the change you make will have the same result everywhere.
If you're not using an IDE, have you considered that by DRY-ing up constants, you're adding about 2-3 steps to even see what the value of a constant is?
Jump to the top of your file, figure out where the import is from, open the other file, then find constant name.
You also force your code reviewers to do this in e.g. GitHub, where there's no convenient 'jump to definition'.
IMHO, if your starting point is that you won't use sed, can't use a good IDE, and won't configure your editor nicely, then you're just creating a lot of unnecessary work for yourself, regardless of whether you're doing DRY.
Power tools are appropriate if you're building a house.