To change the permission mode in Linux, you can use the "chmod" command with a combination of letters and numbers.
Here are the steps to change the permission mode:
- Open the terminal.
- Identify the file or directory for which you want to change the permissions.
- Use the "chmod" command followed by the permission mode and the file or directory name. The permission mode can be set using three numbers or a combination of letters and symbols.
Using numbers: Each digit represents the permission for a specific user group - owner, group, and others. The digits can range from 0 to 7, where:
0: No permission
1: Execute permission
2: Write permission
3: Write and execute permissions
4: Read permission
5: Read and execute permissions
6: Read and write permissions
7: Read, write, and execute permissions
For example, to set read, write, and execute permissions for the owner, and only read and execute permissions for the group and others, you can use the following command:
chmod 755 filename
Using letters and symbols: The letters and symbols represent specific permission types:
"o": Others (users who are neither the owner nor in the group)
"a": All users (same as "ugo" combined)
The symbols used are:
"+": Add permission
"-": Remove permission
"=": Set permission explicitly
For example, to set read, write, and execute permissions for the owner, and remove write permission for the group and others, you can use the following command:
chmod u=rwx,g-w,o-wx filename
Note: You may need administrative privileges or ownership of the file to change the permission mode for certain files or directories.