Section (1) unlink
Name
unlink — call the unlink function to remove the specified file
Synopsis
unlink
FILE
unlink
OPTION
DESCRIPTION
Call the unlink function to remove the specified FILE.
−−help
-
display this help and exit
−−version
-
output version information and exit
REPORTING BUGS
GNU coreutils online help: <https://www.gnu.org/software/coreutils/>
Report any translation bugs to <https://translationproject.org/team/>
SEE ALSO
Full documentation <https://www.gnu.org/software/coreutils/unlink>
or available locally via: info _zsingle_quotesz_(coreutils) unlink invocation_zsingle_quotesz_
COPYRIGHT |
---|
Copyright © 2019 Free Software Foundation, Inc. License GPLv3+: GNU GPL version 3 or later <https://gnu.org/licenses/gpl.html>. This is free software: you are free to change and redistribute it. There is NO WARRANTY, to the extent permitted by law. |
Section (2) unlink
Name
unlink, unlinkat — delete a name and possibly the file it refers to
Synopsis
#include <unistd.h>
int
unlink( |
const char *pathname) ; |
#include <fcntl.h> /* Definition of AT_* constants */ #include <unistd.h>
int
unlinkat( |
int dirfd, |
const char *pathname, | |
int flags) ; |
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Note | |||||
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DESCRIPTION
unlink
() deletes a name from
the filesystem. If that name was the last link to a file and
no processes have the file open, the file is deleted and the
space it was using is made available for reuse.
If the name was the last link to a file but any processes still have the file open, the file will remain in existence until the last file descriptor referring to it is closed.
If the name referred to a symbolic link, the link is removed.
If the name referred to a socket, FIFO, or device, the name for it is removed but processes which have the object open may continue to use it.
unlinkat()
The unlinkat
() system call
operates in exactly the same way as either unlink
() or rmdir(2) (depending on
whether or not flags
includes the
AT_REMOVEDIR
flag) except for
the differences described here.
If the pathname given in pathname
is relative, then it
is interpreted relative to the directory referred to by the
file descriptor dirfd
(rather than relative
to the current working directory of the calling process, as
is done by unlink
() and
rmdir(2) for a relative
pathname).
If the pathname given in pathname
is relative and
dirfd
is the
special value AT_FDCWD
, then
pathname
is
interpreted relative to the current working directory of
the calling process (like unlink
() and rmdir(2)).
If the pathname given in pathname
is absolute, then
dirfd
is
ignored.
flags
is a bit
mask that can either be specified as 0, or by ORing
together flag values that control the operation of
unlinkat
(). Currently, only
one such flag is defined:
AT_REMOVEDIR
-
By default,
unlinkat
() performs the equivalent ofunlink
() onpathname
. If theAT_REMOVEDIR
flag is specified, then performs the equivalent of rmdir(2) onpathname
.
See openat(2) for an
explanation of the need for unlinkat
().
RETURN VALUE
On success, zero is returned. On error, −1 is
returned, and errno
is set
appropriately.
ERRORS
- EACCES
-
Write access to the directory containing
pathname
is not allowed for the process_zsingle_quotesz_s effective UID, or one of the directories inpathname
did not allow search permission. (See also path_resolution(7).) - EBUSY
-
The file
pathname
cannot be unlinked because it is being used by the system or another process; for example, it is a mount point or the NFS client software created it to represent an active but otherwise nameless inode (NFS silly renamed). - EFAULT
-
pathname
points outside your accessible address space. - EIO
-
An I/O error occurred.
- EISDIR
-
pathname
refers to a directory. (This is the non-POSIX value returned by Linux since 2.1.132.) - ELOOP
-
Too many symbolic links were encountered in translating
pathname
. - ENAMETOOLONG
-
pathname
was too long. - ENOENT
-
A component in
pathname
does not exist or is a dangling symbolic link, orpathname
is empty. - ENOMEM
-
Insufficient kernel memory was available.
- ENOTDIR
-
A component used as a directory in
pathname
is not, in fact, a directory. - EPERM
-
The system does not allow unlinking of directories, or unlinking of directories requires privileges that the calling process doesn_zsingle_quotesz_t have. (This is the POSIX prescribed error return; as noted above, Linux returns EISDIR for this case.)
- EPERM (Linux only)
-
The filesystem does not allow unlinking of files.
- EPERM or EACCES
-
The directory containing
pathname
has the sticky bit (S_ISVTX
) set and the process_zsingle_quotesz_s effective UID is neither the UID of the file to be deleted nor that of the directory containing it, and the process is not privileged (Linux: does not have theCAP_FOWNER
capability). - EPERM
-
The file to be unlinked is marked immutable or append-only. (See ioctl_iflags(2).)
- EROFS
-
pathname
refers to a file on a read-only filesystem.
The same errors that occur for unlink
() and rmdir(2) can also occur for
unlinkat
(). The following
additional errors can occur for unlinkat
():
- EBADF
-
dirfd
is not a valid file descriptor. - EINVAL
-
An invalid flag value was specified in
flags
. - EISDIR
-
pathname
refers to a directory, andAT_REMOVEDIR
was not specified inflags
. - ENOTDIR
-
pathname
is relative anddirfd
is a file descriptor referring to a file other than a directory.
VERSIONS
unlinkat
() was added to
Linux in kernel 2.6.16; library support was added to glibc in
version 2.4.
NOTES
Glibc notes
On older kernels where unlinkat
() is unavailable, the glibc
wrapper function falls back to the use of unlink
() or rmdir(2). When pathname
is a relative
pathname, glibc constructs a pathname based on the symbolic
link in /proc/self/fd
that
corresponds to the dirfd
argument.
BUGS
Infelicities in the protocol underlying NFS can cause the unexpected disappearance of files which are still being used.
SEE ALSO
rm(1), unlink(1), chmod(2), link(2), mknod(2), open(2), rename(2), rmdir(2), mkfifo(3), remove(3), path_resolution(7), symlink(7)
COLOPHON
This page is part of release 4.16 of the Linux man-pages
project. A
description of the project, information about reporting bugs,
and the latest version of this page, can be found at
https://www.kernel.org/doc/man−pages/.
This manpage is Copyright (C) 1992 Drew Eckhardt; and Copyright (C) 1993 Ian Jackson and Copyright (C) 2006, 2014 Michael Kerrisk. %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on all copies. Permission is granted to copy and distribute modified versions of this manual under the conditions for verbatim copying, provided that the entire resulting derived work is distributed under the terms of a permission notice identical to this one. Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date. The author(s) assume no responsibility for errors or omissions, or for damages resulting from the use of the information contained herein. The author(s) may not have taken the same level of care in the production of this manual, which is licensed free of charge, as they might when working professionally. Formatted or processed versions of this manual, if unaccompanied by the source, must acknowledge the copyright and authors of this work. %%%LICENSE_END Modified 1993-07-24 by Rik Faith <faithcs.unc.edu> Modified 1996-09-08 by Arnt Gulbrandsen <agulbratroll.no> Modified 1997-01-31 by Eric S. Raymond <esrthyrsus.com> Modified 2001-05-17 by aeb Modified 2004-06-23 by Michael Kerrisk <mtk.manpagesgmail.com> |