Changing file permissions with chmod

To change the permissions on a file, follow:

$ chmod o+w a_file

Here we grant the other users the write access. The o character stands for other,  w stands for write.

list of flags:

• u = user
• g = group
• o = other 
• r  = read
• w = write
• x = execute

Note that this is just one way we can change permissions to files and directories. Another way is to a numerical syntax, however my goal is not to learn you every single way we can make operations on our system. If you like to read up on other ways to do it, pleas do as my old teacher you to say "Google it!"