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NAME | SYNOPSIS | DESCRIPTION | OPTIONS | EXAMPLES | CONFORMANCE TO POSIX 1003.1e DRAFT STANDARD 17 | AUTHOR | SEE ALSO | COLOPHON |
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SETFACL(1) Access Control Lists SETFACL(1)
setfacl - set file access control lists
setfacl [-bkndRLPvh] [{-m|-x} acl_spec] [{-M|-X} acl_file] file
...
setfacl --restore={file|-}
This utility sets Access Control Lists (ACLs) of files and
directories. On the command line, a sequence of commands is
followed by a sequence of files (which in turn can be followed by
another sequence of commands, ...).
The -m and -x options expect an ACL on the command line. Multiple
ACL entries are separated by comma characters (`,'). The -M and -X
options read an ACL from a file or from standard input. The ACL
entry format is described in Section ACL ENTRIES.
The --set and --set-file options set the ACL of a file or a
directory. The previous ACL is replaced. ACL entries for this
operation must include permissions.
The -m (--modify) and -M (--modify-file) options modify the ACL of
a file or directory. ACL entries for this operation must include
permissions.
The -x (--remove) and -X (--remove-file) options remove ACL
entries. It is not an error to remove an entry which does not
exist. Only ACL entries without the perms field are accepted as
parameters, unless POSIXLY_CORRECT is defined.
When reading from files using the -M and -X options, setfacl
accepts the output getfacl produces. There is at most one ACL
entry per line. After a Pound sign (`#'), everything up to the end
of the line is treated as a comment.
If setfacl is used on a file system which does not support ACLs,
setfacl operates on the file mode permission bits. If the ACL does
not fit completely in the permission bits, setfacl modifies the
file mode permission bits to reflect the ACL as closely as
possible, writes an error message to standard error, and returns
with an exit status greater than 0.
PERMISSIONS
The file owner and processes capable of CAP_FOWNER are granted the
right to modify ACLs of a file. This is analogous to the
permissions required for accessing the file mode. (On current
Linux systems, root is the only user with the CAP_FOWNER
capability.)
-b, --remove-all
Remove all extended ACL entries. The base ACL entries of the
owner, group and others are retained.
-k, --remove-default
Remove the Default ACL. If no Default ACL exists, no warnings
are issued.
-n, --no-mask
Do not recalculate the effective rights mask. The default
behavior of setfacl is to recalculate the ACL mask entry,
unless a mask entry was explicitly given. The mask entry is
set to the union of all permissions of the owning group, and
all named user and group entries. (These are exactly the
entries affected by the mask entry).
--mask
Do recalculate the effective rights mask, even if an ACL mask
entry was explicitly given. (See the -n option.)
-d, --default
All operations apply to the Default ACL. Regular ACL entries
in the input set are promoted to Default ACL entries. Default
ACL entries in the input set are discarded. (A warning is
issued if that happens).
--restore={file|-}
Restore a permission backup created by `getfacl -R' or
similar. All permissions of a complete directory subtree are
restored using this mechanism. If the input contains owner
comments or group comments, setfacl attempts to restore the
owner and owning group. If the input contains flags comments
(which define the setuid, setgid, and sticky bits), setfacl
sets those three bits accordingly; otherwise, it clears them.
This option cannot be mixed with other options except
`--test'. If the file specified is '-', then it will be read
from standard input.
--test
Test mode. Instead of changing the ACLs of any files, the
resulting ACLs are listed.
-R, --recursive
Apply operations to all files and directories recursively.
This option cannot be mixed with `--restore'.
-L, --logical
Logical walk, follow symbolic links to directories. The
default behavior is to follow symbolic link arguments, and
skip symbolic links encountered in subdirectories. Only
effective in combination with -R. This option cannot be mixed
with `--restore'.
-P, --physical
Physical walk, do not follow symbolic links to directories.
This also skips symbolic link arguments. Only effective in
combination with -R. This option cannot be mixed with
`--restore'.
-v, --version
Print the version of setfacl and exit.
-h, --help
Print help explaining the command line options.
-- End of command line options. All remaining parameters are
interpreted as file names, even if they start with a dash.
- If the file name parameter is a single dash, setfacl reads a
list of files from standard input.
ACL ENTRIES
The setfacl utility recognizes the following ACL entry formats
(blanks inserted for clarity):
[d[efault]:] [u[ser]:]uid [:perms]
Permissions of a named user. Permissions of the file owner
if uid is empty.
[d[efault]:] g[roup]:gid [:perms]
Permissions of a named group. Permissions of the owning
group if gid is empty.
[d[efault]:] m[ask][:] [:perms]
Effective rights mask
[d[efault]:] o[ther][:] [:perms]
Permissions of others.
Whitespace between delimiter characters and non-delimiter
characters is ignored.
Proper ACL entries including permissions are used in modify and
set operations. (options -m, -M, --set and --set-file). Entries
without the perms field are used for deletion of entries (options
-x and -X).
For uid and gid you can specify either a name or a number.
Character literals may be specified with a backslash followed by
the 3-digit octal digits corresponding to the ASCII code for the
character (e.g., \101 for 'A'). If the name contains a literal
backslash followed by 3 digits, the backslash must be escaped
(i.e., \\).
The perms field is a combination of characters that indicate the
read (r), write (w), execute (x) permissions. Dash characters in
the perms field (-) are ignored. The character X stands for the
execute permission if the file is a directory or already has
execute permission for some user. Alternatively, the perms field
can define the permissions numerically, as a bit-wise combination
of read (4), write (2), and execute (1). Zero perms fields or
perms fields that only consist of dashes indicate no permissions.
AUTOMATICALLY CREATED ENTRIES
Initially, files and directories contain only the three base ACL
entries for the owner, the group, and others. There are some rules
that need to be satisfied in order for an ACL to be valid:
* The three base entries cannot be removed. There must be
exactly one entry of each of these base entry types.
* Whenever an ACL contains named user entries or named group
objects, it must also contain an effective rights mask.
* Whenever an ACL contains any Default ACL entries, the three
Default ACL base entries (default owner, default group, and
default others) must also exist.
* Whenever a Default ACL contains named user entries or named
group objects, it must also contain a default effective rights
mask.
To help the user ensure these rules, setfacl creates entries from
existing entries under the following conditions:
* If an ACL contains named user or named group entries, and no
mask entry exists, a mask entry containing the same
permissions as the group entry is created. Unless the -n
option is given, the permissions of the mask entry are further
adjusted to include the union of all permissions affected by
the mask entry. (See the -n option description).
* If a Default ACL entry is created, and the Default ACL
contains no owner, owning group, or others entry, a copy of
the ACL owner, owning group, or others entry is added to the
Default ACL.
* If a Default ACL contains named user entries or named group
entries, and no mask entry exists, a mask entry containing the
same permissions as the default Default ACL's group entry is
added. Unless the -n option is given, the permissions of the
mask entry are further adjusted to include the union of all
permissions affected by the mask entry. (See the -n option
description).
Granting an additional user read access
setfacl -m u:lisa:r file
Revoking write access from all groups and all named users (using
the effective rights mask)
setfacl -m m::rx file
Removing a named group entry from a file's ACL
setfacl -x g:staff file
Copying the ACL of one file to another
getfacl file1 | setfacl --set-file=- file2
Copying the access ACL into the Default ACL
getfacl --access dir | setfacl -d -M- dir
If the environment variable POSIXLY_CORRECT is defined, the
default behavior of setfacl changes as follows: All non-standard
options are disabled. The ``default:'' prefix is disabled. The
-x and -X options also accept permission fields (and ignore them).
Andreas Gruenbacher, <[email protected]>.
Please send your bug reports, suggested features and comments to
the above address.
getfacl(1), chmod(1), umask(1), acl(5)
This page is part of the acl (manipulating access control lists)
project. Information about the project can be found at
⟨http://savannah.nongnu.org/projects/acl⟩. If you have a bug
report for this manual page, see
⟨http://savannah.nongnu.org/bugs/?group=acl⟩. This page was
obtained from the project's upstream Git repository
⟨git://git.savannah.nongnu.org/acl.git⟩ on 2025-08-11. (At that
time, the date of the most recent commit that was found in the
repository was 2025-05-12.) If you discover any rendering
problems in this HTML version of the page, or you believe there is
a better or more up-to-date source for the page, or you have
corrections or improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
[email protected]
May 2000 ACL File Utilities SETFACL(1)
Pages that refer to this page: chacl(1), getfacl(1), nfs4_setfacl(1), tmpfiles.d(5), systemd-journald.service(8)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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