The University of Texas at Austin

Web Publishing on Unix

Changing File Permissions

For the following procedures, make sure you have logged in to an SSH Client and are at the Unix terminal. Instructions on how to log in to an SSH Client can be found at the Help page.

To submit a command line in Unix, press Enter.

Types of users

Files can be granted separate permissions for three sets of users.

  • User (u) - The owner of the file or directory.

  • Groups (g) - Members of the group(s) to which the owner of the file or directory belongs.

  • Others (o) - Everyone else who is not the user or a member of the group.

  • All (a) - Grants the same permissions to users, groups, and outsiders.

Types of permissions

There are three permissions that can be granted to the above sets of users.

  • r - (r)ead access allows users to view.

  • w - (w)rite access allows users to edit.

  • x - e(x)ecute allows users to execute a file.

Permissions can be granted (+), taken away (-), or overwritten (=).

Changing permissions

The chmod command is used to modify each set of users' permissions for a file. To use the chmod command, enter it in the format of chmod who=permissions filename.

Examples:

  • chmod g-w its.txt takes away the group's write permissions for the file its.txt.

  • chmod go=r its.txt overwrites previous permissions on its.txt to read-only for groups and others.

Changing permissions when connected through SFTP

On a PC, if you are using the SSH Secure File Transfer program, file permissions can be managed by right clicking on a file and selecting Properties.

On a Mac, if you are using Fetch, file permissions can be managed by selecting a file and pressing the Apple + I key to conduct a Get Info on the file. Once the Get Info dialogue box appears, expand the Ownership Permissions section to modify file permissions.

Go to the "Using FTP with a UTS account" page for PC or MAC to find out more information on using FTP.

Last updated February 12, 2013 @ 4:01 pm

We Can Help

Get help from an expert at the ITS Help Desk!

* Call us at 512-475-9400

* Submit a help request online

We also have a walk-in service in the first floor lobby of the Flawn Academic Center (FAC). Stop by and let us help you!