No, vi often isn't installed, e.g. on Linux ADSL routers. If there is one editor it will be ed(1), the one true editor. :) That's why everyone should know it

No, vi often isn't installed, e.g. on Linux ADSL routers. If there is one editor it will be ed(1), the one true editor. :) That's why everyone should know it. Besides, it is a bit easier to use ed blind to edit a file from a mental image of the file's contents than it is vi.