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 com-
       mands, ...).

       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  in-
       clude permissions.

       The  -m  (--modify)  and -M (--modify-file) options modify the ACL of a
       file or directory.  ACL entries for this operation must include permis-
       sions.

       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  en-
       tries  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, set-
       facl operates on the file mode permission bits. If the ACL does not fit
       completely  in the permission bits, setfacl modifies the file mode per-
       mission 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  en-
           try  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 en-
           try).

       --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 hap-
           pens).

       --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 in-
           put 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  ex-
           cept  `--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 op-
           tion cannot be mixed with `--restore'.

       -L, --logical
           Logical walk, follow symbolic links to directories. The default be-
           havior  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 inter-
           preted 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 op-
       erations. (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  oc-
       tal  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 permis-
       sion 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 exe-
       cute  (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  en-
       tries  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 ex-
       isting 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  permis-
           sions  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, own-
           ing group, or others entry is added to the Default ACL.

       *   If  a  Default  ACL  contains named user entries or named group en-
           tries, and no mask entry exists, a mask entry containing  the  same
           permissions  as the default Default ACL's group entry is added. Un-
           less 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 be-
       havior of setfacl changes as follows: All non-standard options are dis-
       abled.   The  ``default:''  prefix  is disabled.  The -x and -X options
       also accept permission fields (and ignore them).

AUTHOR
       Andreas Gruenbacher, <andreas.gruenbacher@gmail.com>.

       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)