rename - change the name of a file
char *from, *to;
Rename causes the link named from to be renamed as to. If to exists, then it is first
removed. Both from and to must be of the same type (that is, both directories or both
non-directories), and must reside on the same file system.
Rename guarantees that an instance of to will always exist, even if the system should
crash in the middle of the operation.
If the final component of from is a symbolic link, the symbolic link is renamed, not the
file or directory to which it points.
The system can deadlock if a loop in the file system graph is present. This loop takes
the form of an entry in directory "a", say "a/foo", being a hard link to directory "b",
and an entry in directory "b", say "b/bar", being a hard link to directory "a". When such
a loop exists and two separate processes attempt to perform "rename a/foo b/bar" and
"rename b/bar a/foo", respectively, the system may deadlock attempting to lock both direc-
tories for modification. Hard links to directories should be replaced by symbolic links
by the system administrator.
A 0 value is returned if the operation succeeds, otherwise rename returns -1 and the
global variable errno indicates the reason for the failure.
Rename will fail and neither of the argument files will be affected if any of the follow-
ing are true:
[EINVAL] Either pathname contains a character with the high-order bit set.
[ENAMETOOLONG] A component of either pathname exceeded 255 characters, or the entire
length of either path name exceeded 1023 characters.
[ENOENT] A component of the from path does not exist, or a path prefix of to does
[EACCES] A component of either path prefix denies search permission.
[EACCES] The requested link requires writing in a directory with a mode that denies
[EPERM] The directory containing from is marked sticky, and neither the containing
directory nor from are owned by the effective user ID.
[EPERM] The to file exists, the directory containing to is marked sticky, and nei-
ther the containing directory nor to are owned by the effective user ID.
[ELOOP] Too many symbolic links were encountered in translating either pathname.
[ENOTDIR] A component of either path prefix is not a directory.
[ENOTDIR] From is a directory, but to is not a directory.
[EISDIR] To is a directory, but from is not a directory.
[EXDEV] The link named by to and the file named by from are on different logical
devices (file systems). Note that this error code will not be returned if
the implementation permits cross-device links.
[ENOSPC] The directory in which the entry for the new name is being placed cannot be
extended because there is no space left on the file system containing the
[EDQUOT] The directory in which the entry for the new name is being placed cannot be
extended because the user's quota of disk blocks on the file system con-
taining the directory has been exhausted.
[EIO] An I/O error occurred while making or updating a directory entry.
[EROFS] The requested link requires writing in a directory on a read-only file sys-
[EFAULT] Path points outside the process's allocated address space.
[EINVAL] From is a parent directory of to, or an attempt is made to rename ``.'' or
[ENOTEMPTY] To is a directory and is not empty.
4.2 Berkeley Distribution May 22, 1986 RENAME(2)