1SETFACL(1) Access Control Lists SETFACL(1)
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6 setfacl - set file access control lists
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9 setfacl [-bkndRLPvh] [{-m|-x} acl_spec] [{-M|-X} acl_file] file ...
10 setfacl --restore=file
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15 This utility sets Access Control Lists (ACLs) of files and directories.
16 On the command line, a sequence of commands is followed by a sequence
17 of files (which in turn can be followed by another sequence of com‐
18 mands, ...).
19 The -m and -x options expect an ACL on the command line. Multiple ACL
21 entries are separated by comma characters (`,'). The -M and -X options
22 read an ACL from a file or from standard input. The ACL entry format is
23 described in Section ACL ENTRIES.
24 The --set and --set-file options set the ACL of a file or a directory.
26 The previous ACL is replaced. ACL entries for this operation must
27 include permissions.
28 The -m (--modify) and -M (--modify-file) options modify the ACL of a
30 file or directory. ACL entries for this operation must include permis‐
31 sions.
32 The -x (--remove) and -X (--remove-file) options remove ACL entries. It
34 is not an error to remove an entry which does not exist. Only ACL
35 entries without the perms field are accepted as parameters, unless
36 POSIXLY_CORRECT is defined.
37 When reading from files using the -M and -X options, setfacl accepts
39 the output getfacl produces. There is at most one ACL entry per line.
40 After a Pound sign (`#'), everything up to the end of the line is
41 treated as a comment.
42 If setfacl is used on a file system which does not support ACLs, set‐
44 facl operates on the file mode permission bits. If the ACL does not fit
45 completely in the permission bits, setfacl modifies the file mode per‐
46 mission bits to reflect the ACL as closely as possible, writes an error
47 message to standard error, and returns with an exit status greater than
48 0.
49 PERMISSIONS
52 The file owner and processes capable of CAP_FOWNER are granted the
53 right to modify ACLs of a file. This is analogous to the permissions
54 required for accessing the file mode. (On current Linux systems, root
55 is the only user with the CAP_FOWNER capability.)
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59 -b, --remove-all
60 Remove all extended ACL entries. The base ACL entries of the owner,
61 group and others are retained.
62 -k, --remove-default
64 Remove the Default ACL. If no Default ACL exists, no warnings are
65 issued.
66 -n, --no-mask
68 Do not recalculate the effective rights mask. The default behavior
69 of setfacl is to recalculate the ACL mask entry, unless a mask
70 entry was explicitly given. The mask entry is set to the union of
71 all permissions of the owning group, and all named user and group
72 entries. (These are exactly the entries affected by the mask
73 entry).
74 --mask
76 Do recalculate the effective rights mask, even if an ACL mask entry
77 was explicitly given. (See the -n option.)
78 -d, --default
80 All operations apply to the Default ACL. Regular ACL entries in the
81 input set are promoted to Default ACL entries. Default ACL entries
82 in the input set are discarded. (A warning is issued if that hap‐
83 pens).
84 --restore=file
86 Restore a permission backup created by `getfacl -R' or similar. All
87 permissions of a complete directory subtree are restored using this
88 mechanism. If the input contains owner comments or group comments,
89 setfacl attempts to restore the owner and owning group. If the
90 input contains flags comments (which define the setuid, setgid, and
91 sticky bits), setfacl sets those three bits accordingly; otherwise,
92 it clears them. This option cannot be mixed with other options
93 except `--test'.
94 --test
96 Test mode. Instead of changing the ACLs of any files, the resulting
97 ACLs are listed.
98 -R, --recursive
100 Apply operations to all files and directories recursively. This
101 option cannot be mixed with `--restore'.
102 -L, --logical
104 Logical walk, follow symbolic links to directories. The default
105 behavior is to follow symbolic link arguments, and skip symbolic
106 links encountered in subdirectories. Only effective in combination
107 with -R. This option cannot be mixed with `--restore'.
108 -P, --physical
110 Physical walk, do not follow symbolic links to directories. This
111 also skips symbolic link arguments. Only effective in combination
112 with -R. This option cannot be mixed with `--restore'.
113 -v, --version
115 Print the version of setfacl and exit.
116 -h, --help
118 Print help explaining the command line options.
119 -- End of command line options. All remaining parameters are inter‐
121 preted as file names, even if they start with a dash.
122 - If the file name parameter is a single dash, setfacl reads a list
124 of files from standard input.
125 ACL ENTRIES
128 The setfacl utility recognizes the following ACL entry formats (blanks
129 inserted for clarity):
130 [d[efault]:] [u[ser]:]uid [:perms]
133 Permissions of a named user. Permissions of the file owner if
134 uid is empty.
135 [d[efault]:] g[roup]:gid [:perms]
137 Permissions of a named group. Permissions of the owning group if
138 gid is empty.
139 [d[efault]:] m[ask][:] [:perms]
141 Effective rights mask
142 [d[efault]:] o[ther][:] [:perms]
144 Permissions of others.
145 Whitespace between delimiter characters and non-delimiter characters is
147 ignored.
148 Proper ACL entries including permissions are used in modify and set
150 operations. (options -m, -M, --set and --set-file). Entries without
151 the perms field are used for deletion of entries (options -x and -X).
152 For uid and gid you can specify either a name or a number. Character
154 literals may be specified with a backslash followed by the 3-digit
155 octal digits corresponding to the ASCII code for the character (e.g.,
156 \101 for 'A'). If the name contains a literal backslash followed by 3
157 digits, the backslash must be escaped (i.e., \\).
158 The perms field is a combination of characters that indicate the read
160 (r), write (w), execute (x) permissions. Dash characters in the perms
161 field (-) are ignored. The character X stands for the execute permis‐
162 sion if the file is a directory or already has execute permission for
163 some user. Alternatively, the perms field can define the permissions
164 numerically, as a bit-wise combination of read [4m(4), write [4m(2), and exe‐
165 cute [4m(1). Zero perms fields or perms fields that only consist of
166 dashes indicate no permissions.
167 AUTOMATICALLY CREATED ENTRIES
169 Initially, files and directories contain only the three base ACL
170 entries for the owner, the group, and others. There are some rules that
171 need to be satisfied in order for an ACL to be valid:
172 * The three base entries cannot be removed. There must be exactly one
174 entry of each of these base entry types.
175 * Whenever an ACL contains named user entries or named group objects,
177 it must also contain an effective rights mask.
178 * Whenever an ACL contains any Default ACL entries, the three Default
180 ACL base entries (default owner, default group, and default others)
181 must also exist.
182 * Whenever a Default ACL contains named user entries or named group
184 objects, it must also contain a default effective rights mask.
185 To help the user ensure these rules, setfacl creates entries from
187 existing entries under the following conditions:
188 * If an ACL contains named user or named group entries, and no mask
190 entry exists, a mask entry containing the same permissions as the
191 group entry is created. Unless the -n option is given, the permis‐
192 sions of the mask entry are further adjusted to include the union
193 of all permissions affected by the mask entry. (See the -n option
194 description).
195 * If a Default ACL entry is created, and the Default ACL contains no
197 owner, owning group, or others entry, a copy of the ACL owner, own‐
198 ing group, or others entry is added to the Default ACL.
199 * If a Default ACL contains named user entries or named group
201 entries, and no mask entry exists, a mask entry containing the same
202 permissions as the default Default ACL's group entry is added.
203 Unless the -n option is given, the permissions of the mask entry
204 are further adjusted to include the union of all permissions
205 affected by the mask entry. (See the -n option description).
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208 Granting an additional user read access
209 setfacl -m u:lisa:r file
210 Revoking write access from all groups and all named users (using the
212 effective rights mask)
213 setfacl -m m::rx file
214 Removing a named group entry from a file's ACL
216 setfacl -x g:staff file
217 Copying the ACL of one file to another
219 getfacl file1 | setfacl --set-file=- file2
220 Copying the access ACL into the Default ACL
222 getfacl --access dir | setfacl -d -M- dir
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225 If the environment variable POSIXLY_CORRECT is defined, the default
226 behavior of setfacl changes as follows: All non-standard options are
227 disabled. The ``default:'' prefix is disabled. The -x and -X options
228 also accept permission fields (and ignore them).
229
231 Andreas Gruenbacher, <a.gruenbacher@bestbits.at>.
232 Please send your bug reports, suggested features and comments to the
234 above address.
235
237 getfacl(1), chmod(1), umask(1), acl(5)
238May 2000 ACL File Utilities SETFACL(1)