How do I create unique temporary file names?

In Unix-like systems, user-space processes do not normally deal with files at all; the operating system provides a level of abstraction which means that almost all interaction with files from user-space is through hard links. Hard links allow a name to be associated with a file (or they can be anonymous - and therefore temporary); files do not have names in the OS. For example, a user-space program cannot delete a file; it can delete a link to a file (for example, using the shell commands rm or mv or, in the anonymous case, simply by exiting), and if the kernel determines that there are no more existing links to the file, it may then delete the file. In fact, it really is only the kernel that deals with files, but it serves to handle all user-space interaction which (virtual) files in a manner that is transparent to the user-space programs.