<P> Files on a computer can be created, moved, modified, grown, shrunk, and deleted . In most cases, computer programs that are executed on the computer handle these operations, but the user of a computer can also manipulate files if necessary . For instance, Microsoft Word files are normally created and modified by the Microsoft Word program in response to user commands, but the user can also move, rename, or delete these files directly by using a file manager program such as Windows Explorer (on Windows computers) or by command lines (CLI). </P> <P> In Unix - like systems, user - space programs do not operate directly, at a low level, on a file . Only the kernel deals with files, and it handles all user - space interaction with files in a manner that is transparent to the user - space programs . The operating system provides a level of abstraction, which means that interaction with a file from user - space is simply through its filename (instead of its filehandle). For example, rm filename will not delete the file itself, but only a link to the file . There can be many links to a file, but when they are all removed, the kernel considers that file's memory space free to be reallocated . This free space is commonly considered a security risk (due to the existence of file recovery software). Any secure - deletion program uses kernel - space (system) functions to wipe the file's data . </P> <P> In modern computer systems, files are typically accessed using names (filenames). In some operating systems, the name is associated with the file itself . In others, the file is anonymous, and is pointed to by links that have names . In the latter case, a user can identify the name of the link with the file itself, but this is a false analogue, especially where there exists more than one link to the same file . </P> <P> Files (or links to files) can be located in directories . However, more generally, a directory can contain either a list of files or a list of links to files . Within this definition, it is of paramount importance that the term "file" includes directories . This permits the existence of directory hierarchies, i.e., directories containing sub-directories . A name that refers to a file within a directory must be typically unique . In other words, there must be no identical names within a directory . However, in some operating systems, a name may include a specification of type that means a directory can contain an identical name for more than one type of object such as a directory and a file . </P>

What are different types of files in computer