A file is named, for the convenience of its human users, and is referred to by
its name. A name is usually a string of characters, such as example.c. Some
systems differentiate between uppercase and lowercase characters in names,
whereas other systems do not. When a file is named, it becomes independent
of the process, the user, and even the system that created it. For instance, one
user might create the file example.c, and another user might edit that file by
specifying its name. The file’s owner might write the file to a USB disk, send it
as an e-mail attachment, or copy it across a network, and it could still be called
example.c on the destination system.