NAME
setfacl - set file access control lists
SYNOPSIS
setfacl [-bkndRLPvh] [{-m|-x} acl_spec] [{-M|-X}
acl_file] file ...
setfacl --restore=file
DESCRIPTION
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 options -m, and -x expect an ACL on the
command line. Multiple ACL entries are separated by comma
characters (`,'). The options -M, and -X 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 enries. 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.)
OPTIONS
- -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, and setfacl is run by root, the owner and owning group of
all files are restored as well. This option cannot be mixed with
other options except `--test'.
- --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. The default behavior is to
follow symbolic link arguments, and to skip symbolic links
encountered in subdirectories. This option cannot be mixed with
`--restore'.
- -P, --physical
- Physical walk, skip all symbolic links. This also skips
symbolic link arguments. This option cannot be mixed with
`--restore'.
- --version
- Print the version of setfacl and exit.
- --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.
The perms field is a combination of characters that
indicate the permissions: read (r), write (w),
execute (x), execute only if the file is a directory or
already has execute permission for some user (X).
Alternatively, the perms field can be an octal digit (0-7).
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 inclu de the union of all permissions
affected by the mask entry. (See the -n option
description).
EXAMPLES
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
CONFORMANCE TO POSIX 1003.1e DRAFT STANDARD 17
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).
AUTHOR
Andreas Gruenbacher, <>.
Please send your bug reports, suggested features and comments to
the above address.
SEE ALSO
getfacl(1),
chmod(1),
umask(1),
acl(5)