Slackware Linux Essentials
Prev		Next

Chapter 9 Filesystem -Structure

- -

Table of Contents
9.1 Ownership
9.2 Permissions
9.3 Links
9.4 Mounting Devices
9.5 NFS Mounts

- -

We have already discussed the directory structure in Slackware Linux. By this point, -you should be able to find files and directories that you need. But there is more to the -filesystem than just the directory structure.

- -

Linux is a multiuser operating system. Every aspect of the system is multiuser, even -the filesystem. The system stores information like who owns a file and who can read it. -There are other unique parts about the filesystems, such as links and NFS mounts. This -section explains these, as well as the multiuser aspects of the filesystem.

- -

9.1 Ownership

- -

The filesystem stores ownership information for each file and directory on the system. -This includes what user and group own a particular file. The easiest way to see this -information is with the ls command:

- - - - - -

-% ls -l /usr/bin/wc
--rwxr-xr-x   1 root     bin    7368 Jul 30  1999 /usr/bin/wc
-

- -

We are interested in the third and fourth columns. These contain the username and -group name that owns this file. We see that the user “root” and the group “bin” own this file.

- -

We can easily change the file owners with the chown(1) (which -means “change owner”) and chgrp(1) (which means -“change group”) commands. To change the file owner to daemon, we would use chown:

- - - - - -

-# chown daemon /usr/bin/wc
-

- -

To change the group owner to “root”, we would -use chgrp:

- - - - - -

-# chgrp root /usr/bin/wc
-

- -

We can also use chown to specify the user and group owners -for a file:

- - - - - -

-# chown daemon:root /usr/bin/wc
-

- -

In the above example, the user could have used a period instead of a colon. The result -would have been the same; however, the colon is considered better form. Use of the period -is deprecated and may be removed from future versions of chown -to allow usernames with periods in them. These usernames tend to be very popular with -Windows Exchange Servers and are encountered most commonly in email addresses such as: -mr.jones@example.com. In slackware, administrators are advised -to stay away from such usernames because some scripts still use the period to indicate -the user and group of a file or directory. In our example, chmod -would interpret mr.jones as user “mr” and group -“jones”.

- -

File ownership is a very important part of using a Linux system, even if you are the -only user. You sometimes need to fix ownerships on files and device nodes.

Prev	Home	Next
Virtual Terminals		Permissions