Why is my custom script running on Red Hat Enterprise Linux is throwing an error: "Invalid cross-device link"?

Typically, this error results when the scripts in questions are using ln command and have tried to create a hard-link across filesystems.

Since it is not possible to create hard-links for files across filesystems, the ln command errors. Below is an example of this:

[root@localhost ~]# df -h
Filesystem Size Used Avail Use% Mounted on
/dev/mapper/V...