runat(1)							   User Commands							  runat(1)

NAME

       runat - execute command in extended attribute name space

SYNOPSIS

       /usr/bin/runat file [command]

DESCRIPTION

       The  runat  utility is used to execute shell commands in a file's hidden attribute directory. Effectively, this utility changes the current
       working directory to be the hidden attribute directory associated with the file argument and then executes the  specified  command  in  the
       bourne  shell  (/bin/sh).  If no command argument is provided, an interactive shell is spawned. The environment variable $SHELL defines the
       shell to be spawned. If this variable is undefined, the default shell, /bin/sh, is used.

       The file argument can be any file, including a directory, that can support extended attributes. It is not necessary that this file have any
       attributes, or be prepared in any way, before invoking the runat command.

OPERANDS

       The following operands are supported:

       file	       Any file, including a directory, that can support extended attributes.

       command	       The command to be executed in an attribute directory.

ERRORS

       A  non-zero  exit  status  will	be  returned  if  runat  cannot  access  the file argument, or the file argument does not support extended
       attributes.

USAGE

       See fsattr(5) for a detailed description of extended file attributes.

       The process context created by the runat command has its current working directory set  to  the	hidden	directory  containing  the  file's
       extended  attributes. The parent of this directory (the ".." entry) always refers to the file provided on the command line. As such, it may
       not be a directory. Therefore, commands (such as pwd) that depend upon the parent entry being well-formed (that is, referring to  a  direc-
       tory) may fail.

       In  the absence of the command argument, runat will spawn a new interactive shell with its current working directory set to be the provided
       file's hidden attribute directory. Notice that some shells (such as zsh and tcsh) are not well behaved when the directory parent is  not  a
       directory, as described above. These shells should not be used with runat.

EXAMPLES

       Example 1: Using runat to list extended attributes on a file

       example% runat file.1 ls -l
       example% runat file.1 ls

       Example 2: Creating extended attributes

       example% runat file.2 cp /tmp/attrdata attr.1
       example% runat file.2 cat /tmp/attrdata > attr.1

       Example 3: Copying an attribute from one file to another

       example% runat file.2 cat attr.1 | runat file.1 "cat > attr.1"

       Example 4: Using runat to spawn an interactive shell

       example% runat file.3 /bin/sh

       This spawns a new shell in the attribute directory for file.3. Notice that the shell will not be able to determine what your current direc-
       tory is. To leave the attribute directory, either exit the spawned shell or change directory (cd) using an absolute path.

       Recommended methods for performing basic attribute operations:

       display

	   runat file ls [options]

       read

	   runat file cat attribute

       create/modify

	   runat file cp absolute-file-path attribute

       delete

	   runat file rm attribute

       permission changes

	   runat file chmod mode attribute
	   runat file chgrp group attribute
	   runat file chown owner attribute

       interactive shell

	   runat file /bin/sh
	    or set your $SHELL to /bin/sh and
	   runat file

       The above list includes commands that are known to work with runat. While many other commands may work, there  is  no  guarantee  that  any
       beyond this list will work. Any command that relies on being able to determine its current working directory is likely to fail. Examples of
       such commands follow:

       Example 5: Using man in an attribute directory

       example% runat file.1 man runat
       getcwd: Not a directory

       Example 6: Spawning a tcsh shell in an attribute directory

       example% runat file.3 /usr/bin/tcsh
       tcsh: Not a directory
       tcsh: Trying to start from "/home/user"

       A new tcsh shell has been spawned with the current working directory set to the user's home directory.

       Example 7: Spawning a zsh shell in an attribute directory

       example% runat file.3 /usr/bin/zsh
       example%

       While the command appears to have worked, zsh has actually just changed the current working directory to '/'. This can  be  seen  by  using
       /bin/pwd:

       example% /bin/pwd
       /

ENVIRONMENT VARIABLES

       SHELL	       Specifies the command shell to be invoked by runat.

EXIT STATUS

       The following exit values are returned:

       125	The attribute directory of the file referenced by the file argument cannot be accessed.

       126	The exec of the provided command argument failed.

       Otherwise, the exit status returned is the exit status of the shell invoked to execute the provided command.

ATTRIBUTES

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

       +-----------------------------+-----------------------------+
       |      ATTRIBUTE TYPE	     |	    ATTRIBUTE VALUE	   |
       +-----------------------------+-----------------------------+
       |Availability		     |SUNWcsu			   |
       +-----------------------------+-----------------------------+
       |CSI			     |Enabled			   |
       +-----------------------------+-----------------------------+
       |Interface Stability	     |Evolving			   |
       +-----------------------------+-----------------------------+

SEE ALSO

       open(2), attributes(5), fsattr(5)

NOTES

       It  is  not  always obvious why a command fails in runat when it is unable to determine the current working directory. The errors resulting
       can be confusing and ambiguous (see the tcsh and zsh examples above).

SunOS 5.10							    22 Jun 2001 							  runat(1)