If you do
rm myFile where
myFile is a hard link, what happens?
In Unix all normal files are Hardlinks. Hardlinks in a Unix (and most (all?) ) filesystems are references to an to what's called an
inode has a reference counter, when you have one "link" to the file (which is the normal modus operandi) the counter is 1. When you create a second, third, fourth, etc link, the counter is incremented (increased ) each time by one. When you delete (
rm) a link the counter is decremented ( reduced ) by one. If the link counter reaches 0 the filesystem removes the
inode and marks the space as available for use.
In short, as long as you do not delete the last link the file will remain.
Edit: The file will remain even if the last link is removed. This is one of the ways to ensure security of data contained in a file is not accessible to any other process. Removing the data from the filesystem completely is done only if the data has 0 links to it as given in its metadata and is not being used by any process.
This IMHO is by far the easiest way to understand hard-links (and its difference from softlinks).