Linux operating system uses a permissions schema to define user rights for each file. These permissions establish:

-who can read the file. If the file is a directory, read means list the contents of the directory.

-who can write/modify the file. If the file is a directory, this permission defines if you can make any changes to the directory contents, for example create or delete files.

-who can execute the file. If the file is a directory, this permission defines if you can enter the directory and access its contents, for example run a search in the directory or execute a program in it.

Permissions are assigned to the file owner, to the file owner group, and to all users. For example, you can set a document to be readable and writable by the owner only, and just readable by everybody else.

When you issue an ls –l command, to list all contents of a directory, you will see file permissions like this next to each file:

-rwxrwxrwx

This means this file can be read, written and executed by anybody. The first dash means this file is not a directory. For directories, there will be a d letter instead of a dash.

The first set of “rwx” refers to the file owner. The second set, to the owner group. The last set, to all other users. Let’s look at some examples:

-rwxr - - r - -

This file can be read, written and executed by its owner. It can only be read by other users. When a permission is not set, you see a dash in its place.

-rw-rw-r- -

This file can be read and written by its owner and the owner group. It can only be read by other users.

You can set these permissions using the chmod command. For example, this command:

chmod ugo=rwx filename

assigns read, write and execute permissions to file owner user(u), group(g) and others (o). This other example:

chmod ug=rw,o=r filename

assigns read and write permissions to user and group, and only read permission to others.

Permissions can also be expressed and set using the octal numeric system. Each permission is associated to a number:

Read = 4
Write = 2
Execute = 1

You need to come up with a number for the file owner, another number for the group and a last one for the other users. If you want to assign read, write and execute permissions to file owner, you add up the three values, thus getting a 7. If you want to assign same permissions to group and others, you come up with three sevens. You can set these permissions like this:

chmod 777 filename

If you set permissions for a file with the following command:

chmod 764 filename

then you’re establishing these permissions: read, write and execute for file owner (4+2+1=7), read and write for group (4+2=6) and only read for others (4).

The following commands are equivalent:

chmod ug=rw,o=r filename

chmod 664 filename

The file permissions schema lets you implement security policies. It is not a good idea to set file permissions high (e.g.: 777) for all files. It is important to think about it and assign the right permissions to the files, so users can do their job, and we are sure each file is accessed only by the right people.

Sergio Roth is an experienced freelance web programmer. You can contact him for Linux hosting and website development services at http://www.ayreshost.com.

Groupware

The internet is full of 1.5 million to 7 million indexed pages of groupware packages available on the market today. Every business needs groupware to control, manage, or track documents.

Groupware is similar to other systems that enable document management, often using a centralized system to work through business collaboration processes to create budgets, market reports, presentations, contracts, and countless other documents necessary to run a business.

Ad Hoc Collaboration

Often times, however, businesses do not, or cannot, follow an outlined document collaboration process. Deadlines near, clients change their minds, management changes their minds, information changes, and needs change. In searching for groupware that enables businesses to track collaborative documents, even in an ad hoc environment, businesses need to find groupware that works the way businesses do.

Tracking

In an ad hoc business environment, tracking your document versions can be a chaos. To meet deadlines, many documents are created. But, work is often hurried through, multiple drafts are saved on multiple drives, emails are shot back and forth, and changes are continually made. But when the deadline arrives, the document may barely be missing key parts because drafts and changes were difficult to track, drafts may be missing, nobody knows the draft order, and nobody knows who made the suggested changes. Businesses need groupware that can handle ad hoc collaboration.

Businesses often have to put documents together ad hoc, but the end result doesn’t have to be a mess. In searching through the groupware available, there are technologies to keep an eye out for which enable document tracking during hectic, ad hoc, document collaboration.

Digital Thread Technology

Groupware with Digital Thread Technology strings a digital thread through each draft of a document as it changes hands, even through email. An informational tag is inserted into the meta data of the electronic document which acts as a genetic tracker for the document. Digital Thread works in conjunction with Digital Signature and Version History to display the who, what, when, where, and how of a document.

Digital Signature

Digital Signatures provide basic version information every time a tracked document is attached to a Microsoft Outlook e-mail. A link is provided that allows users to see in real time if they still have the latest version of a document.

Version History

In addition to a signature that provides basic version information, groupware with a Version History feature enables a display of the document genealogy or family tree. Version History is a flow chart or visual display of the who, what, when, where, and how of the document.

Merging

After utilizing these groupware technologies, merging the changes is very simple. With just three clicks, you can compare different versions of a document. All of the changes are recorded and tracked, and all of the options are at your finger tips when deciding how the information will be presented in its final format. The ad hoc mess has essentially been cleaned up behind you and presented to you in an organized system to allow the final document to be complete, as well as having a helpful version trail to refer to in case other changes are necessary in the future.

Installation

This is often the most costly part of collaboration software. In sifting through the millions of groupware packages indexed online, the most cost efficient groupware will not require new IT infrastructure. Groupware which can be downloaded is quicker, more efficient, and more budget-sensitive.

The market knows that businesses need services to track and manage documents, especially in an ad hoc environment. Use these tips to make an effective search for a groupware that works the way businesses do.

Joe Miller is a specialist in online advertising. Groupware information is available at NextPage.com.