chattr (in /usr/sbin)

If something refuses to run, try:

chattr -R -suSiadAc /usr/sbin

Example: if dovecot doesn't run or install/upgrade, try doing...

if still no go, do :

Documentation:

source: http://www.oreillynet.com/linux/cmd/cmd.csp?path=c/chattr

chattr

chattr [options] mode files

Modify file attributes. Specific to Linux Second and Third Extended Filesystem (ext2 and ext3). Behaves similarly to symbolic chmod, using +, -, and =. mode is in the form opcode attribute. See also lsattr.
Options
-R

Modify directories and their contents recursively.

-V

Print modes of attributes after changing them.

-v version

Set the file's version.

Opcodes
+

Add attribute.

-

Remove attribute.

=

Assign attributes (removing unspecified attributes).

Attributes
A

Don't update access time on modify.

a

Append only for writing. Can be set or cleared only by a privileged user.

c

Compressed.

d

No dump.

i

Immutable. Can be set or cleared only by a privileged user.

j

Journalled file. This is useful only in cases where you are using an ext3 filesystem mounted with the data="ordered" or data="writeback" attributes. The data="journalled" option for the filesystem causes this operation to be performed for all files in the system and makes this option irrelevant.

S

Synchronous updates.

s

Secure deletion. The contents are zeroed on deletion, and the file cannot be undeleted or recovered in any way.

u

Undeletable. This causes a file to be saved even after it has been deleted, so that a user can undelete it later.

Example

chattr +a myfile As superuser