XCACLS.exe (Server Resource Kit)

Display or modify Access Control Lists (ACLs) for files and folders.

Syntax
      XCACLS filename [options]

      XCACLS filename

Key
   If no options are specified XCACLS will display the ACLs for the file(s)

   options can be any combination of:

   /T       Traverse all subfolders and change all matching files found. 

   /E       Edit ACL instead of replacing it. 

   /x       Edit ACL instead of replacing it; affect only ACEs that this user already owns*

   /R user  Revoke all access rights from the given user.

   /D user  Deny specified user access, this will over-ride 
            all other permissions the user has.

   /C       Continue on access denied errors. 
   /Y       Replace user's rights without verify

   /P user:permision[;FolderSpec]
       Replace user's rights. see /G option below 

   /G user:permision[;FolderSpec]
       Grant specified user access rights, permision can be: 
         r  Read 
         c  Change (write) 
         f  Full control 
         p  Change Permissions (Special access)
         o  Take Ownership (Special access)
         x  EXecute (Special access)
         e  REad (Special access)
         w  Write (Special access)
         d  Delete (Special access)
         t  Used only by FolderSpec. see below

* Option only valid in Windows 2003

FolderSpec is a permission applied to a folder. If FolderSpec is not specified then permission will apply to both files and folders.
This allows you to set different permissions that will apply (through inheritance) when new files are added to the folder.

FolderSpec = ;T@ where @ is one of the rights above, when this is specified new files will inherit FolderSpec instead of permission. At least one folder access right must follow the T For example ;TF will apply full control (but ;FT is not valid)

Wildcards can be used to specify more that one file in a command. You can specify more than one user in a command. You can combine access rights.

Versions:
When running this command it is important to use the correct version (NTFS standards have changed with different versions of Windows and XCACLS has been updated to suit)
Early versions of xcacls may give unpredictable results against an NTFS v5 partition.

xcacls.vbs is described in Q825751 and can be downloaded here - xcacls.vbs is an unsupported utility that addresses a limitation with the original xcacls.exe, specifically the inability to append permissions to a folder whose child objects have the inheritance flag set. The .vbs version does not suppport unc paths.

Examples:

:: Allow guests the right to read and execute in MyFolder
XCACLS MyFolder /E /G guests:rx

:: Allow guests the Full Control permission in MyFolder and all subfolders
XCACLS MyFolder /T /E /G guests:f

:: Grant guests only read access to all files in and below MyFolder,
:: new folders created will be Read Access only, new files will not inherit any rights.
XCACLS MyFolder /T /P guests:R;Tr

:: Grant guests only execute access to all files in and below MyFolder
XCACLS MyFolder /T /P guests:x

:: Take Ownership of "Application Data" folder and grant Administrators Full control (:OF)
:: Preserve existing permissions (/E) & apply to subfolders (/T)
XCACLS "Application Data" /E /g Administrators:OF /T

"I spent most of the eighties, most of my life, riding around in somebody else's car, in possession of, or ingested of, something illegal, on my way from something illegal to something illegal with many illegal things happening all around me" - Iggy Pop

Related:

CACLS - Display or modify Access Control Lists (ACLs) for files and folders
DIR /Q - Display the owner for a list of files (try it for Program files)
AccessEnum - GUI to browse a tree view of user privs
NTRIGHTS - Edit user account rights
PERMS - Show permissions for a user
SHOWACL - Show file Access Control Lists (win 2000)
SHOWACCS - Show ACLs on the registry, file system, file and print shares
SUBINACL - Change an ACL's user/domain
ATTRIB - Display or change file attributes
Permissions & Local/Global Workgroups

Permissions explained - Microsoft.com
Access-based Enumeration - Set file listing to only display files you can read (Win 2003)
Q245031 - Change Registry Permissions from the command line
Q822790 - Xcacls /E - Objects do not inherit permissions as expected.

ACL utils: SetAcl or FileACL

Equivalent Linux BASH commands:

chmod - Change access permissions
chown - Change file owner and group