SUSE LINUX Documentation - Index of

3.2.2 Modifying File Permissions
Changing Access Permissions
The access permissions of a file or directory can be changed by the owner and, of
course, by root with the command chmod followed by the parameters changing
the permissions and one or more filenames. The parameters form different categories:
1. Users concerned
• u (user)—owner of the file
• g (group)—group that owns the file
• o (others)—additional users (if no parameter is given, the changes apply to all
categories)
2. A character for deletion (–), setting (=), or insertion (+)
3. The abbreviations
• r—read
• w—write
• x—execute
4. Filename or filenames separated by spaces
If, for example, the user tux in Example 3.2, “Sample Output Showing Directory
Permissions” (page 104) also wants to grant other users write (w) access to the directory
ProjectData, he can do this using the command chmod o+w
ProjectData.
If, however, he wants to deny all users other than himself write permissions, he
can do this by entering the command chmod go-w ProjectData. To prohibit
all users from adding a new file to the folder ProjectData, enter chmod -w
ProjectData. Now, not even the owner can create a new file in the directory
without first reestablishing write permissions.
Working with the Shell 105