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Back to Web Providers... GROUPS OF PROVIDERS

Each directory and file on the server has associated with it an owner userid and a group. Generally only the owner can make changes to a file or directory, but others can be given permission through group access.

The owner of a directory can request that a group be created to control updates to the pages in the directory. We will need the name of the directory where the pages reside on the server and a list of userids who are to be authorized to update them. Contact us at with the information.


Once you have created a file or a subdirectory on the server that is to be maintained by the group (by uploading via FTP, for example) you will need to set its group and flags. Some FTP clients can change the settings or you can SSH to and issue a few commands:

 cd   path
 chgrp   groupname   object
 chmod   g+rwx   object

First change directories to your assigned directory (here represented as path). Then use the chgrp command to set the group associated with the file or subdirectory object. Next use the chmod command to give the group access to the file or subdirectory. Once you have set the attributes they are retained even if a new copy of a file is uploaded.

Note that chgrp and chmod have -R options which cause the change to apply to the files and subdirectories contained within a directory. Be certain that you really want all of the contents of a directory changed in this way before you use this option!

Most FTP clients can display the settings or you can SSH to the server and list them with the command:

 ls -l

You will get a response something like:

 -rw-rw-r-- 1 userid groupname 1023 Jun 16 12:54 welcome.html

where userid is the user that the file or directory is assigned to (referred to as the owner) and groupname is the group the file is assigned to.


You can list the members of your group (or groups) with the command:

 grep groupname /etc/group

where groupname is the name of your group. To change the members of your group send a note to webmaster with the details.

Each user can belong to as many as fourteen groups and each group can have as many as 200 members. You can see a list of the groups you are in with the command:



Group maintenance of pages requires coördination among the group members. A frequent problem is getting updates out of sync when several individuals have what they think is the current copy of a file on their workstations, make an update, and then upload it. This causes updates to be lost. There is no automatic mechanism to prevent this, so good communication within the group is essential.

Another frequent error is failing to set the group and flags when a file is created. Only the owner userid can change these settings.

This page was last updated on 2003-05-13. Please direct questions and comments regarding this page to


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