doku.cifnet.com

This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong.
The //**chmod**// command in Linux and Unix-like systems like FreeBSD is used to change the permissions of files and directories. Permissions determine who can access and perform certain actions on a file or directory.

Let's dive in and understand how to use the **chmod** command.

In Linux and Unix-like systems, permissions are represented by 9 characters. Three sets of three characters, each set representing read, write, and execute permissions for the owner, group, and others.

To use **chmod** command, you need to specify the permissions you want to set and the file or directory you want to modify. You can specify permissions using either symbolic or numeric methods.

=== Symbolic Method: ===
In the symbolic method, you use a combination of letters and operators to specify the permissions. For example:

To give read, write, and execute permissions to the owner of a **package**, you can use the following command:
<code>$ chmod u+rwx package</code>

To remove write permissions for others on a directory, you can use the following command:
<code>$ chmod o-w directory</code>

To give the owner execute permissions on a file named //**script.sh**//, run the following command:
<code>$ chmod +x script.sh</code>

To remove execute permissions for the group and others on a file named //**file.txt**//
<code>$ chmod go-x file.txt</code>

To add read and write permissions for everyone on a directory named //**docs**//, run the following command:
<code>$ chmod a+rw docs</code>

To add execute permission to the owner of a file named //**utility**//, run the following command:
<code>chmod u+x file.txt</code>

Note that 
  * **u** stands for **owner**, 
  * **g** stands for **group**, 
  * **o** stands for **others**, 
  * **+** **adds** the specified permission, 
  * **-** **removes** the specified permission, 
  * **r** stands for **read**, 
  * **w** stands for **write**, 
  * **x** stands for **execute**.

----

=== Numeric Method: ===
In the numeric method, you use numbers to represent permissions. 
  * Read permission is represented by 4, 
  * Write permission is represented by 2, 
  * Execute permission is represented by 1.

To set permissions, you add the numbers representing the permissions you want to set. For example:

To set full permissions for the owner and no permissions for group and others on a file:
<code>$ chmod 700 file.txt</code>

To set read, write, and execute permissions for the owner, read and execute permissions for the group, and no permissions for others, you can use the following command:
<code>$ chmod 754 file.txt</code>

To set only read and execute permissions for the owner and no permissions for the group and others, you can use the following command:
<code>$ chmod 544 directory</code>

To set the permissions of a file named notes.txt so that the owner has read and write permissions, the group has read permissions, and others have no permissions, run the following command:
<code>$ chmod 640 notes.txt</code>


Using **chmod** command, you can easily manage the permissions of files and directories in your Linux or Unix-like system. It's important to understand how to set permissions as it helps in maintaining the security of your system.

Try experimenting with different combinations of permissions and see how it affects the accessibility of files and directories. Keep in mind, improper permissions can cause security issues, so always be careful when using the **chmod** command.

In conclusion, **chmod** is a useful and powerful command. By understanding how to use it, you can manage permissions of your files and directories efficiently and securely.
doku.cifnet.com

User Tools

Site Tools

Page Tools
