Content-type: text/html Man page of chmod

chmod

Section: User Commands (1)
Updated: 9 Feb 2009
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NAME

chmod - change the permissions mode of a file  

SYNOPSIS

chmod [-fR] absolute-mode file...

chmod [-fR] symbolic-mode-list file...

chmod [-fR] acl_operation file...

 

DESCRIPTION

The chmod utility changes or assigns the mode of a file.

chmod can also be used to modify Access Control Lists (ACLs) on files and directories.  

Absolute Mode

An absolute mode specification has the following format:

chmod [options] absolute-mode file . . .

where absolute-mode is specified using octal numbers nnnn defined as follows:

n

a number from 0 to 7. An absolute mode is constructed from the OR of any of the following modes:

4000

Set user ID on execution.

20#0

Set group ID on execution if # is 7, 5, 3, or 1.

Enable mandatory locking if # is 6, 4, 2, or 0.

For directories, files are created with BSD semantics for propagation of the group ID. With this option, files and subdirectories created in the directory inherit the group ID of the directory, rather than of the current process. For directories, the set-gid bit can only be set or cleared by using symbolic mode.

1000

Turn on sticky bit. See chmod(2).

0400

Allow read by owner.

0200

Allow write by owner.

0100

Allow execute (search in directory) by owner.

0700

Allow read, write, and execute (search) by owner.

0040

Allow read by group.

0020

Allow write by group.

0010

Allow execute (search in directory) by group.

0070

Allow read, write, and execute (search) by group.

0004

Allow read by others.

0002

Allow write by others.

0001

Allow execute (search in directory) by others.

0007

Allow read, write, and execute (search) by others.

For directories, the setgid bit cannot be set (or cleared) in absolute mode; it must be set (or cleared) in symbolic mode using g+s (or g-s).  

Symbolic Mode

A symbolic mode specification has the following format:

chmod [options] symbolic-mode-list file . . .

where symbolic-mode-list is a comma-separated list (with no intervening whitespace) of symbolic mode expressions of the form:

[who] operator [permissions]

Operations are performed in the order given. Multiple permissions letters following a single operator cause the corresponding operations to be performed simultaneously.

who

zero or more of the characters u, g, o, and a specifying whose permissions are to be changed or assigned:

u

user's permissions

g

group's permissions

o

others' permissions

a

all permissions (user, group, and other)

If who is omitted, it defaults to a, but the setting of the file mode creation mask (see umask in sh(1) or csh(1) for more information) is taken into account. When who is omitted, chmod does not override the restrictions of your user mask.

operator

either +, -, or =, signifying how permissions are to be changed:

+

Add permissions.

If permissions are omitted, nothing is added.

If who is omitted, add the file mode bits represented by permissions, except for the those with corresponding bits in the file mode creation mask.

If who is present, add the file mode bits represented by the permissions.

-

Take away permissions.

If permissions are omitted, do nothing.

If who is omitted, clear the file mode bits represented by permissions, except for those with corresponding bits in the file mode creation mask.

If who is present, clear the file mode bits represented by permissions.

=

Assign permissions absolutely.

If who is omitted, clear all file mode bits; if who is present, clear the file mode bits represented by who.

If permissions are omitted, do nothing else.

If who is omitted, add the file mode bits represented by permissions, except for the those with corresponding bits in the file mode creation mask.

If who is present, add the file mode bits represented by permissions.

Unlike other symbolic operations, = has an absolute effect in that it resets all other bits represented by who. Omitting permissions is useful only with = to take away all permissions.

permission

any compatible combination of the following letters:

l

mandatory locking

r

read permission

s

user or group set-ID

t

sticky bit

w

write permission

x

execute permission

X

execute permission if the file is a directory or if there is execute permission for one of the other user classes

u,g,o

indicate that permission is to be taken from the current user, group or other mode respectively.

Permissions to a file can vary depending on your user identification number (UID) or group identification number (GID). Permissions are described in three sequences each having three characters:

UserGroupOther
rwxrwxrwx

This example (user, group, and others all have permission to read, write, and execute a given file) demonstrates two categories for granting permissions: the access class and the permissions themselves.

The letter s is only meaningful with u or g, and t only works with u.

Mandatory file and record locking (l) refers to a file's ability to have its reading or writing permissions locked while a program is accessing that file.

In a directory which has the set-group-ID bit set (reflected as either -----s--- or -----l--- in the output of 'ls -ld'), files and subdirectories are created with the group-ID of the parent directory---not that of current process.

It is not possible to permit group execution and enable a file to be locked on execution at the same time. In addition, it is not possible to turn on the set-group-ID bit and enable a file to be locked on execution at the same time. The following examples, therefore, are invalid and elicit error messages:

chmod g+x,+l file
chmod g+s,+l file

Only the owner of a file or directory (or the super-user) can change that file's or directory's mode. Only the super-user can set the sticky bit on a non-directory file. If you are not super-user, chmod masks the sticky-bit but does not return an error. In order to turn on a file's set-group-ID bit, your own group ID must correspond to the file's and group execution must be set.

 

ACL Operation

An ACL Operation specification has the following format:

chmod [options] A[number]- file ...
chmod [options] A-acl_specification file ...
chmod [options] A[index]{+|=}acl_specification file ...

Where acl_specification is a comma-separated list (with no intervening whitespace) of an ACL specification of the form:

A[index]+acl_specification

Prepends the access control entries (ACE) specified in acl_specification to the beginning of the file's ACL. Depending on the file system, the ACL can be reordered when applied to the file. If "optional" number is specified then new ACEs are inserted before specified number.

A-

Removes all ACEs for current ACL on file and replaces current ACL with new ACL that represents only the current mode of the file.

Aindex-

Removes ACE specified by index number.

A-acl_specification

Removes ACEs specified by acl_specification, if they exist in current file's ACL.

A=acl_specification

Replaces a files entire ACL with acl_specification.

A[index]=acl_specification

Replaces ACEs starting at a specific index number in the current ACL on the file. If multiple ACEs are specified, then each subsequent ACE in acl_specification replaces the corresponding ACE in the current ACL.

POSIX-draft ACL Specification (as supported by UFS)

POSIX-draft ACLs (as supported by UFS) are specified as colon (:) separated fields of the following.

user::perms

File owner permissions.

user:username:perms

Permissions for a specific user.

group::perms

File group owner permissions.

group:groupname:perms

Permissions for a specific group.

other::perms

Permissions for user other than the file owner or members of file group owner.

mask:perms

The ACL mask. The mask entry specifies the maximum permissions allowed for user (other than that the owner) and for groups.

default:user::perms

Default file owner permissions.

default:user:username:perms

Default permissions for a specific user.

default:group::perms

Default file group owner permissions.

default:group:groupname:perms

Default permissions for a specific group.

default:other:perms

Default permissions for user other than the file owner or members of the file group owner.

default:mask:perms

Default ACL mask.

The above specification allows for ACLs to be specified such as:

user:tom:rw-,mask:rwx,group:staff:r-x

NFSv4 ACL Specification (as supported by NFSv4 and ZFS)

NFSv4 ACLs provide richer ACL semantics. They provide both allow and deny entries, finer grained permissions, and enhanced inheritance control.

NFSv4 ACLs are specified as colon (:) separated fields of the following.

owner@:<perms>[:inheritance flags]:<allow|deny>

Permissions for file owner.

group@:<perms>[:inheritance flags]:<allow|deny>

Permissions for file group owner.

everyone@:<perms>[:inheritance flags]:<allow|deny>

Permissions for everyone, including file owner and group owner.

user:<username>:<perms>[:inheritance flags]:<allow|deny>

Permissions for a specific user.

group:<groupname>:<perms>[:inheritance flags]:<allow|deny>

Permissions for a specific group.

groupsid:<sid string>:<perms>[:inheritance flags]:<allow|deny>

Permissions for a specific group, but group is specified by SID.

sid:<sid string>:<perms>[:inheritance flags]:<allow|deny>

Permissions for a specific SID, but it doesn't matter if it is a user or a group.

Permissions can be specified in three different chmod ACL formats: verbose, compact, or positional. The verbose format uses words to indicate that the permissions are separated with a forward slash (/) character. Compact format uses the permission letters and positional format uses the permission letters or the hyphen (-) to identify no permissions.

The permissions for verbose mode and their abbreviated form in parentheses for compact and positional mode are described as follows:

read_data (r)

Permission to read the data of a file.

list_directory (r)

Permission to list the contents of a directory.

write_data (w)

Permission to modify a file's data. anywhere in the file's offset range.

add_file (w)

Permission to add a new file to a directory.

append_data (p)

The ability to modify a file's data, but only starting at EOF.

Currently, this permission is not supported.

add_subdirectory (p)

Permission to create a subdirectory to a directory.

read_xattr (R)

Ability to read the extended attributes of a file.

write_xattr (A)

Ability to create extended attributes or write to the extended attribute directory.

execute (x)

Permission to execute a file.

read_attributes (a)

The ability to read basic attributes (non-ACLs) of a file.

write_attributes (W)

Permission to change the times associated with a file or directory to an arbitrary value.

delete (d)

Permission to delete a file.

delete_child (D)

Permission to delete a file within a directory.

read_acl (c)

Permission to read the ACL of a file.

write_acl (C)

Permission to write the ACL of a file.

write_owner (o)

Permission to change the owner of a file.

synchronize (s)

Permission to access file locally at server with synchronize reads and writes.

Currently, this permission is not supported.

Using the compact ACL format, permissions are specified by using 14 unique letters to indicate permissions.

Using the positional ACL format, permissions are specified as positional arguments similar to the ls -V format. The hyphen (-), which indicates that no permission is granted at that position, can be omitted and only the required letters have to be specified.

The letters above are listed in the order they would be specified in positional notation.

Permissions can be specified with these letters in the following way:

rwx--D--------

The hyphens can be removed to compact the string as follows:

rwxD

The optional inheritance flags can be specified in the three formats. The first format uses words to indicate the various inheritance flags separated with a forward slash (/) character.

file_inherit (f)

Inherit to all newly created files.

dir_inherit (d)

Inherit to all newly created directories.

inherit_only (i)

When placed on a directory, do not apply to the directory, only to newly created files and directories. This flag requires that either file_inherit and or dir_inherit is also specified.

no_propagate (n)

Indicates that ACL entries should be inherited to objects in a directory, but inheritance should stop after descending one level. This flag is dependent upon either file_inherit and or dir_inherit also being specified.

The inheritance flags listed can also be specified in the compact format or as positional arguments similar to the ls -V format. A hyphen character indicates that the inheritance flag at that postion is not specified in the positional ACL format.

The inheritance flags can be specified with these letters in any of the following equivalent ways.

file_inherit/dir_inherit/no_propagate

fd-n--

fdn

With this inheritance model, an ACL entry can be specified such as:

user:tom:read_data/write_data/read_attributes:file_inherit:allow
user:fred:read_data:file_inherit/dir_inherit:deny
user:bob:read_data:allow

 

OPTIONS

The following options are supported:

-f

Force. chmod does not complain if it fails to change the mode of a file.

-R

Recursively descends through directory arguments, setting the mode for each file as described above. When symbolic links are encountered, the mode of the target file is changed, but no recursion takes place.

 

OPERANDS

The following operands are supported:

absolute-mode
symbolic-mode-list

Represents the change to be made to the file mode bits of each file named by one of the file operands. See Absolute Mode and Symbolic Mode above in the section for more information.

acl_operation

Represents the modification to be performed on the file's ACL. See ACL Operation in the DESCRIPTION section for more information.

acl_operation is one of the following:

A[number] -
A-acl_specification
A[index]{+|=}acl_specification 

file

A path name of a file whose file mode bits are to be modified.

 

USAGE

See largefile(5) for the description of the behavior of chmod when encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).  

EXAMPLES

Example 1 Denying execute Permission

The following example denies execute permission to everyone:

example% chmod a-x file

Example 2 Allowing read-only Permission

The following example allows only read permission to everyone:

example% chmod 444 file

Example 3 Making a File readable and writable

The following example makes a file readable and writable by the group and others:

example% chmod go+rw file
example% chmod 066 file 

Example 4 Locking a File From Access

The following example locks a file from access:

example% chmod +l file

Example 5 Granting read, write, execute, and set group-ID Permission on a File

The following example grants everyone read, write, and execute permissions on the file, and turns on the set group-ID:

example% chmod a=rwx,g+s file
example% chmod 2777 file

Example 6 Prepending a New ACL Entry on a ZFS File

The following example prepends a new ACL entry on a ZFS file.

First, display the current ACL:

example% ls -v file.3
-rw-r--r--   1 marks    staff          0 Oct  9 15:49 file.3
      0:owner@:execute:deny
      1:owner@:read_data/write_data/append_data/write_xattr/
         write_attributes/write_acl/write_owner:allow
      2:group@:write_data/append_data/execute:deny
      3:group@:read_data:allow
      4:everyone@:write_data/append_data/write_xattr/execute/
        write_attributes/write_acl/write_owner:deny
      5:everyone@:read_data/read_xattr/read_attributes/read_acl/
         synchronize:allow

Issue the following command:

example% chmod A+user:lp:read_data:deny file.3

Display the new ACL:

example% ls -v file.3
-rw-r--r--+  1 marks    staff          0 Oct  9 15:49 file.3
      0:user:lp:read_data:deny
      1:owner@:execute:deny
      2:owner@:read_data/write_data/append_data/write_xattr/
          write_attributes/write_acl/write_owner:allow
      3:group@:write_data/append_data/execute:deny
      4:group@:read_data:allow
      5:everyone@:write_data/append_data/write_xattr/execute/
          write_attributes/write_acl/write_owner:deny
      6:everyone@:read_data/read_xattr/read_attributes/read_acl/
          synchronize:allow

Example 7 Prepending a New POSIX-draft ACL Entry on a UFS File

The following example prepends a new POSIX-draft ACL entry on a UFS file.

First, display the current ACL:

example% ls -v file.2
-rw-r--r--   1 marks    staff          0 Oct  9 15:52 file.2
      0:user::rw-
      1:group::r--           #effective:r--
      2:mask:r--
      3:other:r--

Issue the following command:

example% chmod A+user:lp:-wx file.2

Display the new ACL:

example% ls -v file.2
-rw-r--r--+  1 marks    staff          0 Oct  9 15:52 file.2
      0:user::rw-
      1:user:lp:-wx          #effective:---
      2:group::r--           #effective:r--
      3:mask:r--
      4:other:r--

Example 8 Inserting an ACL Entry in a Specific Position on a ZFS file

The following example inserts an ACL entry in a specific position on a ZFS file system. It also illustrates the compact ACL format.

First, display the ACL to pick a location to insert a new ACE.

example% ls -V file.1
-rw-r--r--+  1 root     root           0 Oct  6 12:16 file.1
     user:lp:rw------------:------:allow
      owner@:--x-----------:------:deny
      owner@:rw-p---A-W-Co-:------:allow
      group@:-wxp----------:------:deny
      group@:r-------------:------:allow
   everyone@:-wxp---A-W-Co-:------:deny
   everyone@:r-----a-R-c--s:------:allow

Next, insert a new entry in location 3. This causes the entries that are currently in position 3 - 6 to be pushed down.

Issue the following command:

example% chmod A3+user:marks:r:deny file.1

Display the new ACL:

example% ls -V file.1
-rw-r--r--+  1 root     staff          0 Feb  3 14:13 file.1
     user:lp:rw------------:------:allow
      owner@:--x-----------:------:deny
      owner@:rw-p---A-W-Co-:------:allow
  user:marks:r-------------:------:deny
      group@:-wxp----------:------:deny
      group@:r-------------:------:allow
   everyone@:-wxp---A-W-Co-:------:deny
   everyone@:r-----a-R-c--s:------:allow

Example 9 Inserting a POSIX-draft ACL in a Specific Position on a UFS File

The file system reorders ACLs when they are stored in the file system. The following example illustrates this behavior.

example% ls -v file.1
-rw-r--r--+  1 root     root           0 Sep 29 16:10 file.1
      0:user::rw-
      1:user:lp:rw-          #effective:r--
      2:group::r--           #effective:r--
      3:mask:r--
      4:other:r--

Now, insert an entry at index position 3. The command works, but the file system reorders the ACL.

example% chmod A3+user:marks:rw- file.1
example% ls -v file.1
-rw-r--r--+  1 root     root           0 Sep 29 16:10 file.1
      0:user::rw-
      1:user:lp:rw-           #effective:r--
      2:user:marks:rw-        #effective:r--
      3:group::r--            #effective:r--
      4:mask:r--
      5:other:r--

Rather than inserting the ACL entry in position 3 as requested, it actually ends up in position 2.

Example 10 Removing an ACL Entry on a ZFS File

The following example removes the lp entry from an ACL:

example% ls -v file.3
-rw-r--r--+  1 marks    staff          0 Oct  9 15:49 file.3
      0:user:lp:read_data:deny
      1:owner@:execute:deny
      2:owner@:read_data/write_data/append_data/write_xattr/
         write_attributes/write_acl/write_owner:allow
      3:group@:write_data/append_data/execute:deny
      4:group@:read_data:allow
      5:everyone@:write_data/append_data/write_xattr/execute/
         write_attributes/write_acl/write_owner:deny
      6:everyone@:read_data/read_xattr/read_attributes/read_acl/
         synchronize:allow

example% chmod A-user:lp:read_data:deny file.3
example% ls -v file.3
-rw-r--r--   1 marks    staff          0 Oct  9 15:49 file.3
      0:owner@:execute:deny
      1:owner@:read_data/write_data/append_data/write_xattr/
         write_attributes/write_acl/write_owner:allow
      2:group@:write_data/append_data/execute:deny
      3:group@:read_data:allow
      4:everyone@:write_data/append_data/write_xattr/execute/
         write_attributes/write_acl/write_owner:deny
      5:everyone@:read_data/read_xattr/read_attributes/read_acl/
         synchronize:allow

Example 11 Removing a POSIX-draft ACL on a UFS File

The following example removes the lp entry from an ACL:

example% ls -v file.2
-rw-r--r--+  1 marks    staff          0 Oct  9 15:52 file.2
      0:user::rw-
      1:user:lp:-wx           #effective:---
      2:group::r--            #effective:r--
      3:mask:r--
      4:other:r--

example% chmod A-user:lp:-wx file.2
example% ls -v file.2
-rw-r--r--   1 marks    staff          0 Oct  9 15:52 file.2
      0:user::rw-
      1:group::r--            #effective:r--
      2:mask:r--
      3:other:r--

Example 12 Removing a Specific ACL Entry by Index Number on a ZFS File

Consider the following ACL:

example% ls -v file
    0:group:staff:read_data/write_data/execute/read_acl:allow
    1:user:bin:read_data:deny
    2:user:bin:read_data:allow
    3:owner@:write_data/append_data:deny
    4:owner@:read_data/write_xattr/execute/write_attributes/write_acl
        /write_owner:allow
    5:group@:write_data/append_data:deny
    6:group@:read_data/execute:allow
    7:everyone@:write_data/append_data/write_xattr/write_attributes
        /write_acl/write_owner:deny
    8:everyone@:read_data/read_xattr/execute/read_attributes/read_acl
        /synchronize:allow

Remove the second user entry for bin.

example% chmod A2- file
example% ls -v file
    0:group:staff:read_data/write_data/execute/read_acl:allow
    1:user:bin:read_data:deny
    2:owner@:write_data/append_data:deny
    3:owner@:read_data/write_xattr/execute/write_attributes/write_acl
       /write_owner:allow
    4:group@:write_data/append_data:deny
    5:group@:read_data/execute:allow
    6:everyone@:write_data/append_data/write_xattr/write_attributes
       /write_acl/write_owner:deny
    7:everyone@:read_data/read_xattr/execute/read_attributes/read_acl
       /synchronize:allow

Example 13 Removing a Specific POSIX-draft ACL Entry on a UFS File

The following example removes the lp entry by index number from the following ACL:

example% ls -v file.1
-rw-r--r--+  1 root     root           0 Sep 29 16:10 file.1
      0:user::rw-
      1:user:lp:rw-              #effective:r--
      2:group::r--               #effective:r--
      3:mask:r--
      4:other:r--

      example% chmod A1- file.1
      example% ls -v
-rw-r--r--+  1 root     root           0 Sep 29 16:10 file.1
      0:user::rw-
      1:group::r--               #effective:r--
      2:mask:r--
      3:other:r--

Example 14 Removing All ACLs From a File

The following command works with either NFSv4/ZFS or POSIX-draft ACLs.

Consider the following ACL:

example% ls -v file.3
-rw-r--r--+  1 marks    staff          0 Oct  9 15:49 file.3
      0:user:lp:read_data/write_data:allow
      1:user:marks:read_acl:allow
      2:owner@:execute:deny
      3:owner@:read_data/write_data/append_data/write_xattr/
         write_attributes/write_acl/write_owner:allow
      4:group@:write_data/append_data/execute:deny
      5:group@:read_data:allow
      6:everyone@:write_data/append_data/write_xattr/execute/
         write_attributes/write_acl/write_owner:deny
      7:everyone@:read_data/read_xattr/read_attributes/read_acl/
         synchronize:allow

The existing ACL is effectively removed and is replaced with an ACL that represents the permission bits of the file.

example% chmod A- file.3
example% ls -v file.3
-rw-r--r--  1 marks    staff          0 Oct  9 15:49 file.3
     0:owner@:execute:deny
     1:owner@:read_data/write_data/append_data/write_xattr/
        write_attributes/write_acl/write_owner:allow
     2:group@:write_data/append_data/execute:deny
     3:group@:read_data:allow
     4:everyone@:write_data/append_data/write_xattr/execute/
        write_attributes/write_acl/write_owner:deny
     5:everyone@:read_data/read_xattr/read_attributes/read_acl/
       synchronize:allow

Example 15 Replacing an Entire ACL Entry on a ZFS File

Use the following chmod syntax if you want to replace an ACL in its entirety:

example% chmod A=owner@:read_data/write_data:allow,group@:read_data/
               write_data:allow,user:lp:read_data:allow file.4
example% ls -v file.4
-rw-rw----+  1 marks    staff          0 Oct  9 16:12 file.4
       0:owner@:read_data/write_data:allow
       1:group@:read_data/write_data:allow
       2:user:lp:read_data:allow

Example 16 Replacing an Entire POSIX-draft ACL on a UFS File

This operation is a little more complicated. The replacement ACL needs the necessary entries to represent the file owner, file group owner, other, mask and any additional entries you wish to set.

example% chmod A=user::rw-,group::rw-,other::---,mask:r--,
              user:lp:r-- file.3
example% ls -v file.3
-rw-r-----+  1 root     root           0 Oct  9 16:14 file.3
        0:user::rw-
        1:user:lp:r--        #effective:r--
        2:group::rw-         #effective:r--
        3:mask:r--
        4:other:---

Example 17 Replacing a Specific Entry on a ZFS File

Consider the following ACL.

example% ls -v file.5
-rw-r--r--+  1 marks    staff          0 Oct  9 16:18 file.5
     0:user:marks:read_data:allow
     1:owner@:execute:deny
     2:owner@:read_data/write_data/append_data/write_xattr/
        write_attributes/write_acl/write_owner:allow
     3:group@:write_data/append_data/execute:deny
     4:group@:read_data:allow
     5:everyone@:write_data/append_data/write_xattr/execute/
        write_attributes/write_acl/write_owner:deny
     6:everyone@:read_data/read_xattr/read_attributes/read_acl/
        synchronize:allow

Now, change the allow access to a deny for user marks:

example% chmod A0=user:marks:read_data:deny file.5
example% ls -v file.5
-rw-r--r--+  1 marks   staff          0 Aug 23 09:11 file.5
0:user:marks:read_data:deny 
1:owner@:read_data/write_data/append_data/write_xattr/write_attributes
     /write_acl/write_owner:allow
2:group@:write_data/append_data/execute:deny
3:group@:read_data:allow
4:everyone@:write_data/append_data/write_xattr/execute/write_attributes
     /write_acl/write_owner:deny
5:everyone@:read_data/read_xattr/read_attributes/read_acl/synchronize
     :allow

Example 18 Replacing a Specific POSIX-draft ACL on a UFS File

Consider the following ACL.

example% ls -v file.4
-rw-r--r--+  1 marks    staff          0 Oct  9 16:21 file.4
        0:user::rw-
        1:user:lp:rwx         #effective:r--
        2:group::r--          #effective:r--
        3:mask:r--
        4:other:r--

Now, change the permission on lp from rwx to r--:

example% chmod A1=user:lp:r-- file.4

example% ls -v file
-rw-r--r--+  1 marks    staff          0 Oct  9 16:21 file.4
        0:user::rw-
        1:user:lp:r--         #effective:r--
        2:group::r--          #effective:r--
        3:mask:r--
        4:other:r--

Example 19 Setting ACL Inheritance Flags on a ZFS File

You can only set inheritance flags on ZFS files. When setting ACLs on directories, several inheritance flags can be optionally set.

Suppose you have an ACL entry for user lp that you want to be inherited to newly created files in a directory. First, you need to create an inheritable ACL entry on the directory:

example% chmod A+user:lp:read_data:file_inherit:allow test.dir
example% ls -dv test.dir
drwxr-xr-x+  2 marks   staff          2 Aug 23 09:08 test.dir/
0:user:lp:read_data:file_inherit:allow
1:owner@::deny 
2:owner@:list_directory/read_data/add_file/write_data/add_subdirectory
     /append_data/write_xattr/execute/write_attributes/write_acl
     /write_owner:allow
3:group@:add_file/write_data/add_subdirectory/append_data:deny
4:group@:list_directory/read_data/execute:allow 
5:everyone@:add_file/write_data/add_subdirectory/append_data/write_xattr
     /write_attributes/write_acl/write_owner:deny
6:everyone@:list_directory/read_data/read_xattr/execute/read_attributes
     /read_acl/synchronize:allow

The lp entry is inherited to newly created files in the directory test.dir.

example% touch test.dir/file.test
example% ls -v test.dir/file.test
-rw-r--r--+  1 marks    staff          0 Oct  9 16:29 test.dir/file.test
     0:user:lp::deny
     1:user:lp:read_data:allow
     2:owner@:execute:deny
     3:owner@:read_data/write_data/append_data/write_xattr/
         write_attributes/write_acl/write_owner:allow
     4:group@:write_data/append_data/execute:deny
     5:group@:read_data:allow
     6:everyone@:write_data/append_data/write_xattr/execute/
         write_attributes/write_acl/write_owner:deny
     7:everyone@:read_data/read_xattr/read_attributes/read_acl/
 synchronize:allow

The user lp entry is inherited to the newly created file. Multiple combinations of the inheritance flags can be specified. For example, if you wanted the lp entry to also be inherited to directories, then the following command can be used:

example% chmod A+user:lp:read_data:file_inherit/\
      dir_inherit:allow test.dir

 

ENVIRONMENT VARIABLES

See environ(5) for descriptions of the following environment variables that affect the execution of chmod: LANG, LC_ALL, LC_CTYPE, LC_MESSAGES, and NLSPATH.  

EXIT STATUS

The following exit values are returned:

0

Successful completion.

>0

An error occurred.

 

ATTRIBUTES

See attributes(5) for descriptions of the following attributes:

ATTRIBUTE TYPEATTRIBUTE VALUE

AvailabilitySUNWcsu

CSI

Interface Stability

 

SEE ALSO

getfacl(1), ls(1), setfacl(1), chmod(2), acl(5), attributes(5), environ(5), largefile(5), standards(5)  

NOTES

Absolute changes do not work for the set-group-ID bit of a directory. You must use g+s or g-s.

chmod permits you to produce useless modes so long as they are not illegal (for instance, making a text file executable). chmod does not check the file type to see if mandatory locking is meaningful.

If the filesystem is mounted with the nosuid option, setuid execution is not allowed.

If you use chmod to change the file group owner permissions on a file with ACL entries, both the file group owner permissions and the ACL mask are changed to the new permissions. Be aware that the new ACL mask permissions can change the effective permissions for additional users and groups who have ACL entries on the file. Use the getfacl(1) or ls(1)command to make sure the appropriate permissions are set for all ACL entries.


 

Index

NAME
SYNOPSIS
DESCRIPTION
Absolute Mode
Symbolic Mode
ACL Operation
OPTIONS
OPERANDS
USAGE
EXAMPLES
ENVIRONMENT VARIABLES
EXIT STATUS
ATTRIBUTES
SEE ALSO
NOTES

This document was created by man2html, using the manual pages.
Time: 02:39:31 GMT, October 02, 2010