Windows: Hard Link

mklink /H "ProjectA\windows.iso" "MasterISOs\windows.iso" mklink /H "ProjectB\windows.iso" "MasterISOs\windows.iso" mklink /H "ProjectC\windows.iso" "MasterISOs\windows.iso" Total disk usage: size of one ISO. Want to keep a "snapshot" of a file before making changes, but don't want to double disk space?

A copy is two independent files. Change one, the other stays old. A hard link is one file with two names. This is where most people get tripped up.

Most Windows users think a file exists in exactly one place. Double-click a file in C:\Documents\Report.docx , and you assume that's the only copy on disk. windows hard link

This isn't a shortcut, and it's not a copy. It's something far more powerful—and far more confusing if you don't understand how it works.

Use them wisely, and always remember: a file with two names is still one file. mklink /H "ProjectA\windows

But Windows has a secret: the . With a hard link, a single file can appear in multiple folders simultaneously, without duplicating any data. Change one, and the others update instantly. Delete one, and the others remain untouched.

fsutil hardlink list "link.txt" Or in PowerShell: Change one, the other stays old

The problem arises when someone else later sees backup.txt , assumes it's a copy, and deletes it—wiping the only remaining link to that data.