UNLINK(2) System Calls Manual UNLINK(2)
unlink - remove directory entry
Name points to a null-terminated string. Unlink removes the entry for
the file pointed to by name from its directory. If this entry was the
last link to the file, the contents of the file are freed and the file
is destroyed. If, however, the file was open in any process, the
actual destruction is delayed until it is closed, even though the
directory entry has disappeared.
Zero is normally returned; -1 indicates that the file does not exist,
that its directory cannot be written, or that the file contains pure
procedure text that is currently in use. Write permission is not
required on the file itself. It is also illegal to unlink a directory
(except for the super-user).
(unlink = 10.)
sys unlink; name