CHMOD stands for “Change Mode” and it is the Linux command which is used to change the access permissions of files and directories. That is why every file and directory has an owner and a group associated with it and they have different permissions to access that particular file. Owner permissions: They determine what operations the owner of the file can chmod 777 binary option on the file. Group permissions: They determine what operations a user belonging to the group associated with that file can execute on the file.
Other permissions: They indicate what operations all other users can execute on the file. In case of directories, a person can view all the files and sub-directories belonging to the directory. In case of directories, a person can create a file or sub-directory in that directory. Well, it does not make any sense.
In case of directories, a person can enter that directory. Linux have a 3×3 format i. We will restrict this part of our discussion up to the use of octal representation for changing files and directories permissions. As an example, we have seen in our one of the previous articles- Getting Started with Linux Shell Scripting Language, we have used a command as chmod 744 helloworld.