[SOLVED] /etc/network/interfaces Permission Denied after Hardware Change

[SuBun7]

After moving my HDD with my ProxMox installation to a new computer - some hardware in the previous one gave out - trying to access '/etc/network/interfaces' by any means shows the message "Permission Denied". I'm not sure why this is happening, as nothing else has changed. The hardware of this computer is even identical to the previous one.

Solved - I was neglecting to type "sudo" before the rest of the command.