Linux is a multiuser system. Hence it requires a system of permissions and accessing rights for specific users.
Chmod command changes the permission specified in the command line and leaves the other file permission unchanged.
This command is given with the Category, Operation, Permission and the filename.
chmod
Where: Category is for User, Groups etc. Operation is to assign or remove permission. Permission is for reading, writing and executing.
chmod +x : It makes the file executable for all the users
chmod u+s : It makes the ordinary user to execute the file like owner of that file.
chmod 644 : It makes the file readable for everyone and readable/writeable for the owner.
chmod 1777: Gives permission to all users for reading, writing and executing.
