Do we still need `-6` for `IP` command?

Question

Seems now `ip` can do the same thing as `ip -6`, so is there any situation that we must use `-6` flag?

LinuxBender · Accepted Answer

ip -6 route del default That does something different than ip route del default

fernvenue · Answer

I'm gonna answer myself, sometimes we do need to add `-6` for IPv6 situation, for example:
- `ip -6 r show`: If we don't add `-6`, we will just get the IPv4 route information. - `ip -6 r add`: If we don't add `-6`, when we add default route or something like that, we may miss IPv6.
So the answer is yes, we can use `ip` without `-6` when we do something for IPv6, but we still need it for specific situation.

mikewarot · Answer

it's the same reason I still have to type grep -i pattern filespec Of course, grep should default to being case insensitive (-i), but it was a different world when it was written.

Do we still need `-6` for `IP` command?

Seems now `ip` can do the same thing as `ip -6`, so is there any situation that we must use `-6` flag?

`ip -6 route del default`
That does something different than
`ip route del default`

it's the same reason I still have to type
`grep -i pattern filespec`
Of course, grep should default to being case insensitive (-i), but it was a different world when it was written.