When you create a file, the system gives it default permissions. On most systems the permissions are 755 (read, write and execute for the owner, and read and execute for others).
This default is setup with the umask command. To use the command, you need to find the right octal number to give it. The permissions in the umask are turned off from 666. This means that a umask of 022 will give you the default of 755. To change your default permissions from 755 to 700,
you would use this command:
umask 077