[NoToP]

The fact that copying doesn't copy seems dangerous. Like what if I wanted to copy for the purpose of modifying the file while retaining the original. A trivial example of this might be I have a meme template and I want to write text in it while still keeping a blank copy of the template.

There's a place for alias file pointers, but lying to the user and pretending like an alias is a copy is bound to lead to unintended and confusing results

[IsTom]

Copy-on-write means that it performs copy only when you make the first change (and only copies part that changes, rest is used from the original file), until then copying is free.

[mlhpdx]

Is it file level or block level copy? The latter, I hope.

Update: whoops, missed it in your comment. Block (changed bytes) level.

[herrkanin]

It’s not a symbolic link - it copies on modification. No need to worry!

[pca006132]

CoW is not aliasing. It will perform the actual copying when you modify the file content.

[hutattedonmyarm]

It‘s Copy On Write. When you modify either one it does get turned into an actual copy

[timabdulla]

It's copy on write.