How to set permissions for a file in Linux operating system?

In Linux, the chmod command is used to set permissions on a file.

Permissions are divided into three categories:

• Owner (user)
• Group (group)
• Others (others)

Each category can be granted rights:

• Read (r)
• Write (w)
• Execute (x)

Examples of setting permissions:

1. Set read, write, and execute rights for the owner, and only read for group and others:

chmod 744 filename

2. Add execute permission for all:

chmod a+x filename

3. Remove write permission for the group:

chmod g-w filename

To view current permissions, use the command:

ls -l filename

Thus, chmod allows flexible management of file access in Linux.