what is 755 permission

Question

I am going through a demo that asked me to change the file permission to 755. I did it by using this command:

chmod 755 filename

I am new to Linux, I know the binary format of chmod But I am not understanding what does 755 set the permission to. Please explain

Answer 1

In Linux 777 permission on the directory means that everyone has access to read/write/execute (execute on a directory means that you can do an ls of the directory).