setfacl

SETFACL(1)                    Access Control Lists                    SETFACL(1)



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 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.)


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,
           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'.

       --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.

       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).

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, <a.gruenbacher@bestbits.at>.

       Please send your bug reports, suggested features and comments to the
       above address.

SEE ALSO
       getfacl(1), chmod(1), umask(1), acl(5)



May 2000                       ACL File Utilities                     SETFACL(1)